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FEDERAL CRITERIA
for
INFORMATION TECHNOLOGY SECURITY
VOLUME II
Registry of Protection Profiles
Version 1.0
December 1992
This document is undergoing review and
is subject to modification or withdrawal.
The contents of this document should not
be referenced in other publications.
NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY
&
NATIONAL SECURITY AGENCY
NOTES TO REVIEWERS
This is the first public draft of work in progress by the joint
National Institute of Standards and Technology (NIST) and
National Security Agency (NSA) Federal Criteria (FC) Project.
This draft Federal Criteria for Information Technology Security
is provided for preliminary review and comment by members of the
national and international computer security community. The
document will evolve into a new Federal Information Processing
Standard (FIPS) intended principally for use by the United States
Federal Government, and also by others as desired and
appropriate. The FIPS is intended to replace the Trusted Computer
System Evaluation Criteria (TCSEC) or "Orange Book."
Our objectives in presenting this draft material are threefold:
first, to give the community a clear view of the FC Project's
direction in moving beyond the TCSEC method of expressing
requirements in order to meet new IT security challenges; second,
to obtain feedback on the innovative approaches taken, the method
of presentation, and granularity; and third, to make a
substantial contribution to the dialogue among nations leading to
the harmonization of IT security requirements and evaluations.
It is important to note a few things about this preliminary FC
draft. First, it is a new and unpolished document and not intended
for any purpose except review and comment. Organizations should
not adopt any contents of this draft document for their use. It
is anticipated that the document will undergo extensive revision
as it works its way through the public FIPS approval process over
the next year or two. Second, the FC is being distributed in two
volumes. Volume I addresses the criteria development process and
is intended principally for use by developers of protection
profiles. The information in Volume I may also be of use to IT
product manufacturers and product evaluators. Volume II presents
completed IT product security criteria in the form of accepted
protection profiles.
The protection profiles associated with the final FIPS will help
consumers identify types of products that meet the protection
requirements within their particular organizations and
environments. However, the FIPS will be supplemented by a series
of implementing guidance documents, many of which will be
designed to help consumers make cost-effective decisions about
obtaining and appropriately using security-capable IT products.
As a preliminary draft of the new FC-FIPS, this document is not
intended for general distribution or compliance. The document
should not be considered a complete or finished product. Your
comments will be used by the Federal Criteria Working Group to
help raise the maturity level of this material prior to being
circulated for further public comment in the FIPS development
process.
ADDITIONAL NOTES TO REVIEWERS
Reviewers who provide substantive comments on the enclosed draft
FC by March 31, 1993 will be invited to attend an Invitational
Workshop on the Federal Criteria. This two-day workshop will be
held in the last week of April 1993 in the Washington-Baltimore
area at a location to be announced. All comments received by the
cut-off date will be correlated into major themes for discussion
by break-out groups at the workshop. The results will be used as
input into the process of re-drafting the FC for a second round of
comment prior to its being formalized as a FIPS.
Please send your comments (electronic format preferred) to
Nickilyn Lynch at the U.S. National Institute of Standards and
Technology (NIST), Computer Systems Laboratory (CSL).
Phone: (301) 975-4267
FAX: (301) 926-2733.
(Internet) Electronic Mail:
lynch@csmes.ncsl.nist.gov
Postal or Express Mail
(Hardcopy or 3.5", 1.44M diskette in MSDOS, Macintosh, or Sun
format):
Federal Criteria Comments
Attn: Nickilyn Lynch
NIST/CSL, Bldg 224/A241
Gaithersburg, MD 20899
NIST National Institute of Standards and Technology
Gaithersburg, MD 20899
COMMERCIAL SECURITY REQUIREMENTS
FOR
MULTI-USER OPERATING SYSTEMS
A family of Protection Profiles for the
Federal Criteria for Information Technology Security
Issue 1.1
January 1993
Supersedes Minimum Security Requirements
for Multi-User Operating Systems
Computer Security Division
Computer Systems Laboratory
National Institute of Standards and Technology
Chapter 1.
Commercial Security Requirements (CSR)
1.1 Introduction
1.1.1 CS Description
1.1.2 Background
1.1.2.1 Trusted Computer System Evaluation Criteria (TCSEC)
1.1.2.2 Commercial Security Efforts
1.1.2.3 System Security Study Committee
1.1.2.4 Minimum Security Functionality Requirements (MSFR)
1.1.2.5 Commercial Security (CS) requirements
1.1.3 Document Organization
COMMERCIAL SECURITY 1 (CS1)
CS1 Rationale
2.2 Introduction
2.2.1 Protection Philosophy
2.2.1.1 Access Authorization
2.2.1.2 Accountability
2.2.1.2.1 Identification and Authentication
2.2.1.2.2 Audit
2.2.1.3 Assurance
2.2.2 Intended Method of Use
2.2.3 Environmental Assumptions
2.2.4 Expected Threats
CS1 Functionality
3. Introduction
3.1 Identification & Authentication
3.2 Audit
3.3 Access Control
3.4 Reference Mediation
3.5 TCB Protection
3.6 TCB Self-Checking
CS1 Assurance
4. Introduction
4.1 TCB Property Definition
4.2 TCB Element Identification
4.3 TCB Interface Definition
4.4 Developer Functional Testing
4.5 User's Guidance
4.6 Administrative Guidance
4.7 Evidence of TCB Protection Properties
4.8 Evidence of Product Development
4.9 Evidence of Functional Testing
4.10 Test Analysis
4.11 Independent Testing
COMMERCIAL SECURITY 2 (CS2)
CS2 Rationale
2.12 Introduction
2.12.1 Protection Philosophy
2.12.1.1 Access Authorization
2.12.1.1.1 System Entry
2.12.1.1.2 Subject and Object Access Mediation
2.12.1.1.3 Privileges
2.12.1.2 Accountability
2.12.1.2.1 Identification and Authentication
2.12.1.2.2 Audit
2.12.1.3 Assurance
2.12.1.4 Intended Method of Use
2.12.2 Environmental Assumptions
2.12.3 Expected Threats
CS2 Functionality
3. Introduction
3.1 Identification & Authentication
3.2 System Entry
3.3 Trusted Path
3.4 Audit
3.5 Access Control
3.6 Security Management
3.7 Reference Mediation
3.8 Logical TCB Protection
3.9 TCB Self-Checking
3.10 TCB Initialization and Recovery
3.11 Privileged Operation
3.12 Ease-of-TCB-Use
CS2 Assurance
4. Introduction
4.1 TCB Property Definition
4.2 TCB Element Identification
4.3 TCB Interface Definition
4.4 TCB Structuring Support
4.5 Developer Functional Testing
4.6 User's Guidance
4.7 Administrative Guidance
4.8 Flaw Remediation Procedures
4.9 Trusted Generation
4.10 Evidence of TCB Protection Properties
4.11 Evidence of Product Development
4.12 Evidence of Functional Testing
4.13 Evidence of Product Support
4.14 Test Analysis
4.15 Independent Testing
4.16 Operational Support Review
COMMERCIAL SECURITY 3 (CS3)
CS3 Rationale
2.17 Introduction
2.17.1 Protection Philosophy
2.17.1.1 Access Authorization
2.17.1.1.1 System Entry
2.17.1.1.2 Subject and Object Access Mediation
2.17.1.1.3 Privileges
2.17.1.2 Accountability
2.17.1.2.1 Identification and Authentication
2.17.1.2.2 Audit
2.17.1.3 Availability of Service
2.17.1.4 Assurance
2.17.1.5 Intended Method of Use
2.17.2 Environmental Assumptions
2.17.3 Expected Threats
CS3 Functionality
3. Introduction
3.1 Identification & Authentication
3.2 System Entry
3.3 Trusted Path
3.4 Audit
3.5 Access Control
3.6 Security Management
3.7 Reference Mediation
3.8 Resource-Allocation Requirements
3.9 TCB Protection
3.10 Physical TCB Protection
3.11 TCB Self-Checking
3.12 TCB Initialization and Recovery
3.13 Privileged Operation
3.14 Ease-of-TCB-Use
CS3 Assurance
4. Introduction
4.1 TCB Property Definition
4.2 TCB Element Identification
4.3 TCB Interface Definition
4.4 Developer Functional Testing
4.5 Penetration Analysis
4.6 User's Guidance
4.7 Administrative Guidance
4.8 Flaw Remediation Procedures
4.9 Trusted Generation
4.10 Life Cycle Definition
4.11 Configuration Management
4.12 Evidence of TCB Protection Properties
4.13 Evidence of Product Development
4.14 Evidence of Functional Testing
4.15 Evidence of Penetration Analysis
4.16 Evidence of Product Support
4.17 Test Analysis
4.18 Independent Testing
4.19 Development Environment Review
4.20 Operational Support Review
4.21 Design Analysis
GLOSSARY
CSR References
Chapter 1.
Commercial Security Requirements (CSR)
1.1 Introduction
Government and commercial institutions rely heavily on
information technology (IT) products to meet their
operational, financial, and information requirements. The
corruption, unauthorized disclosure, or theft of
electronically-maintained resources can have a disruptive
effect on an organization's operations as well as serious and
immediate financial, legal, and public confidence impact.
Products conforming to the Commercial Security (CS)
requirements contained in this document are intended to be
useful to a broad base of users in the private, civil
government, and defense sectors. This includes application
developers, end users, and system administrators. The
Protection Profiles specified in this document provide
organizations with three set of security requirements,
defined as CS1, CS2, and CS3, with CS3 offering the highest
degree of trust.
The Protection Profiles as a whole specify "baseline"
requirements that meet generally accepted security
expectations for a class of products colloquially called
"general purpose, multi-user operating systems." These
requirements apply to multi-user workstations, minicomputers,
and mainframes. Most required mechanisms are configurable so
that customers can satisfy their unique security policies and
objectives.
The intent of the Protection Profiles is to promote the wide
availability of products possessing security enforcing
functions that are of such broad applicability and
effectiveness that they become part of the "normal" mode of
operation. It is anticipated that vendors will respond to user
expectations by increasing the availability of operating
systems that meet these general security requirements. These
requirements represent the integration of a number of security
requirement specifications from various sources into a single
set that is expected to have wide acceptance.
1.1.1 CS Description
The Protection Profiles address the security features and
their development. The Protection Profiles were written to
meet several objectives: to serve as a "metric" for the amount
of security present in a computer system processing sensitive
information; to provide guidance to the developers as to what
security features to build into their planned products; and
to provide a method for uniformly specifying security
requirements in acquisition specifications.
The CS requirements are divided into three hierarchical
Protection Profiles. The profiles are CS1, CS2, and CS3, with
C3 providing the greatest degree of security. Each profile
represents a level of trust that can be placed in a product
and specifies a collection of requirements in the form of
features and assurances. Each profile includes most of the
features and assurances of the previous profile along with
additional, more stringent features and assurances. The
reasoning for requirements leveling for each Protection
Profile can be found in the rationale in Chapter 2. This
reasoning is based on the overall effectiveness of each
Protection Profile in addressing the threats identified in
that chapter.
The Protection Profiles specify computer-based protection
mechanisms for the design, use, and management of information
systems. The Protection Profiles include technical measures
that can be incorporated into multi-user, remote-access,
resource-sharing, and information sharing computer systems.
CS-conformant computer products provide system administrators
with tools to control the sharing of information and resources
based primarily on the identity of users, or, in the case of
CS3, the role associated with the user, as well as the time
of day, terminal location, or type of access requested. The
technical measures also provide tools to protect against both
common user actions that may compromise security and against
deliberate penetration attempts by "hackers." In addition,
there are requirements to log events that may impact the
security of either the product or the information that it is
processing. All functionality requirements are based on
existing and well understood security practices.
1.1.2 Background
These Protection Profiles have been developed by the CS
Working Group of the Federal Criteria Project under NIST
leadership with a high level of private sector participation.
They are based on the Trusted Computer System Evaluation
Criteria (TCSEC) [1] C2 criteria class, with additions from
current computer industry practice, from commercial security
requirements specifications, and from the on-going work of the
Federal Criteria Project. Their development has also been
guided by international security standards efforts and by the
recommendations of the System Security Study Committee.
The following sub-sections provide descriptions of each of
these sources, and gives further background on the motivation
for and development of the Protection Profiles.
1.1.2.1 Trusted Computer System Evaluation Criteria (TCSEC)
The TCSEC [1], originally published in 1983 and revised in
1985, was the first publicly available document that expressed
general security requirements that could apply to a specific
class of technology (e.g., operating systems). It represents
the culmination of many years of effort to address Information
Technolgy (IT) security issues within the Department of
Defense (DoD) classified world. The TCSEC is made up of IT
security features and assurances that have been derived and
engineered to support a very specific DoD security policy -
the prevention of unauthorized disclosure of classified
information (i.e., confidentiality).
During the past few years, commercial enterprises and
government organizations processing sensitive information
have begun to pay increasing attention to IT security needs.
Although the TCSEC-motivated security features have proven
valuable in addressing their security problems, often these
features have been viewed as less than perfect and incomplete
and only to have been specified because a more appropriate set
of security functions has not been available.
The Protection Profiles are intended to be the first step
in "filling this gap" by providing a set of security
requirements appropriate for commercial enterprises and
government organizations concerned with protecting sensitive
information.
1.1.2.2 Commercial Security Efforts
Recognizing that the TCSEC was a valuable starting point,
but not sufficient for their security needs, two commercial
companies - Bellcore and American Express Travel Related
Services (TRS) - independently initiated efforts to develop
security requirements for their environments. At Bellcore,
these efforts resulted in a Bellcore Standard Operating
Environment Security Requirements [3] document and at TRS the
efforts resulted in the internal C2-Plus company security
standard.
The Bellcore document was developed to meet the security
needs of Bellcore and its client companies, the Regional Bell
Operating Companies (RBOCs). The requirements specified in
the Bellcore document were derived both from commonly
recurring security requirements for RBOC computer
applications and from experiences of Bellcore's computer
security assessment group.
In developing the C2-Plus document, TRS found that, while
the TCSEC met many requirements of the commercial sector, the
prescribed features at the C2-level (and its F2-level
counterpart in the ITSEC [2]) fell short in several areas that
were either introduced at higher TCSEC levels or were not
addressed at all in the respective standards. Consequently,
the TRS document was developed as an enhanced, commercialized
version of the C2-level security requirements of the TCSEC.
Using the TRS document as input, the International
Information Integrity Institute (I-4), a consortium of large
international corporations, developed the Commercial
International Security Requirements (CISR) [4]. The rationale
for the development of the CISR include the following:
"Military-oriented information security
requirements (i. e., TCSEC) are not suitable in
many respects for the needs of international
businesses." [4]
The final version of the CISR was published in April 1992.
1.1.2.3 System Security Study Committee
The System Security Study Committee was formed in 1988 in
response to a request from the Defense Advance Research
Projects Agency (DARPA) to address the security and
trustworthiness of U.S. computing and communications systems.
The Committee, which was composed of 16 individuals from
industry and academia, including computer and communications
security researchers, practitioners, and software engineers,
was charged with developing a national research, engineering,
and policy agenda to help the United States achieve a more
trustworthy computing technology base by the end of the
century. In 1991, the Committee published the Computers at
Risk [5] report, which presents the Committee's assessment of
key computer and communications security issues and its
recommendations for enhancing the security and
trustworthiness of the U.S. computing and communications
infrastructure.
The development of the Protection Profiles was guided by
one of the recommendations from this report that:
"...a basic set of security-related principles for
the design, use, and management of systems that are
of such broad applicability and effectiveness that
they ought to be a part of any system with
significant operational requirements" [5] should be
developed.
1.1.2.4 Minimum Security Functionality Requirements (MSFR)
The second draft of the Minimum Security Functionality
Requirements for Multi-User Operating Systems (MSFR) [10] was
published in January of 1992. The MSFR was developed as part
of a project to stimulate the development of IT products
broadly useful to the diverse security needs of the US
Government (civilian and military) and the private sector.
The MSFR specified the minimum level of security that NIST
and NSA felt should be available in any commercially available
multi-user operating system. The MSFR represents an extension
of the TCSEC controlled access protection class, level C2,
with additions based on current industry practice and security
requirements specifications developed in the commercial
environment. Much of the MSFR is derived from the TCSEC, the
Bellcore Standard Operating Environment Security
Requirements, and the CISR with overall guidance from the
Computers at Risk report [5].
1.1.2.5 Commercial Security (CS) requirements
To help support the Federal Criteria, the CS Working Group
was tasked with developing a family of Protection Profiles,
based on an updated version of the MSFR. The three Protection
Profiles included in this document have been developed in
compliance with the prescribed approach and format of the
Federal Criteria [11]. Components of the Federal Criteria were
selected for each Protection Profile and were enhanced with
refinements and assignments that were taken from the November
1992 version of the MSFR. The Protection Profiles are intended
to satisfy the most common security needs of computer system
users.
1.1.3 Document Organization
Chapter 1 (this chapter) provides introductory and
background information. The rest of this document is divided
into three Protection Profiles, CS1, CS2, and CS3. The
development of these Protection Profiles are in accordance
with the Protection Profile format specified by the Federal
Criteria. Chapter 2 provides the rationale for the selection
of the security features and assurance evidence. This
rationale also includes descriptions of the intended use of
the product, the environmental assumptions that were made for
a CS-compliant system, and the expected threats. Chapter 3
specifies the security functionality that a CS-compliant
system is required to provide, and Chapter 4 specifies the
assurance requirements. At the end of the CS requirements,
there is a Glossary and a list of references.
COMMERCIAL SECURITY 1 (CS1)
Products that comply with this Protection Profile
provide access control capabilities to separate
users and data based on finely grained access con-
trols. It incorporates credible controls capable of
enforcing access limitations on an individual
basis, i.e., ostensibly suitable for allowing users
to be able to protect sensitive information and to
keep other users from reading or destroying their
data. Users are individually accountable for their
actions through login procedures, auditing of secu-
rity relevant events, and resource isolation. This
CS1 Protection Profile is equivalent to a Class C2
- Controlled Access Protection from the TCSEC [1].
It consists of TCSEC requirements plus those eval-
uation interpretations that a product must meet
before it can be evaluated at the C2 level.
COMPONENT SUMMARY:
CS1 Functional Component Summary
.------------------------------------------------------.
| | Component | |
| Component Name | Code | Level |
|======================================================|
| Security Policy Support: |
|----------------------------------+-----------+-------|
| Identification & Authentication | I&A | 1 |
|----------------------------------+-----------+-------|
| Audit | AD | 1 |
|----------------------------------+-----------+-------|
| Access Control | AC | 1 |
|----------------------------------+-----------+-------|
| Reference Mediation | RM | 1 |
|----------------------------------+-----------+-------|
| TCB Protection | P | 1 |
|----------------------------------+-----------+-------|
| Self Checking | SC | 1 |
`------------------------------------------------------'
CS1 Assurance Package Summary
.---------------------------------------.
| Assurance Components | T1 |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-1 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-1 |
|--------------------------------+------|
| TCB Interface Definition | IF-1 |
|--------------------------------+------|
| TCB Modular Decomposition | ---- |
|--------------------------------+------|
| TCB Structuring Support | ---- |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | ---- |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-1 |
|--------------------------------+------|
| Trusted Generation | ---- |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | ---- |
|--------------------------------+------|
| Configuration Management | ---- |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP1 |
|--------------------------------+------|
| Product Development | EPD1 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Product Support | ---- |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-1 |
|--------------------------------+------|
| Independent Testing | IT-1 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | ---- |
|--------------------------------+------|
| Operational Support | ---- |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | ---- |
|--------------------------------+------|
| Implementation | ---- |
`---------------------------------------'
CS1 Rationale
2.2 Introduction
As outlined in the Federal Criteria, this rationale de-
scribes the protection philosophy, how the security features
are intended to be used, the assumptions about the environment
in which a compliant product is intended to operate, the
threats within that environment, and the security features and
assurances that counter these threats.
The level of components that were chosen for the CS1 Pro-
tection Profile are equivalent to Class C2 of the TCSEC [1].
They consist of TCSEC requirements plus those evaluation in-
terpretations that a product must meet before it can be eval-
uated at the C2 level.
2.2.1 Protection Philosophy
Any discussion of protection necessarily starts from a pro-
tection philosophy, i.e., what it really means to call the
product "secure." In general, products will control access to
information and other resources through the use of specific
security features so that only properly authorized individu-
als or processes acting on their behalf will be granted ac-
cess. For CS1, three fundamental requirements are derived for
this statement of protection:
o Access authorization
o Accountability
o Assurance
The totality of the functionality that enforces the access
authorization and accountability protection philosophy is
comprised of the hardware, software, and firmware of the
Trusted Computing Base (TCB). CS1 requires the TCB to be pro-
tected from external interference and tampering so that it is
effective at countering identified threats. The assurance
protection philosophy is comprised of the development pro-
cess, operational support, development evidence, and evalua-
tion process assurances. Each of these are explained below.
2.2.1.1 Access Authorization
The access authorization portion of the philosophy of pro-
tection for this profile addresses subject and object access
mediation. CS1 provides protected access to resources and ob-
jects. As defined in the TCSEC and specified in this profile,
access control permits system users and the processes that
represent them to allow or disallow to other users access to
objects under their control:
Access control is "a means of restricting access to
objects based on the identity of subjects and/or
groups to which they belong. The controls are dis-
cretionary in the sense that a subject with a cer-
tain access permission is capable of passing that
permission (perhaps indirectly) on to any other
subject." [1]
These controls permit the granting and revoking of access
privileges to be left to the discretion of the individual us-
ers.
2.2.1.2 Accountability
The accountability portion of the philosophy of protection
for this profile addresses user Identification and Authenti-
cation (I&A) and requirements for security auditing. Each of
these are explained below.
2.2.1.2.1 Identification and Authentication
User identification is required to support access control
and security auditing. This includes the capability to estab-
lish, maintain, and protect a unique identifier for each au-
thorized user. User identification is functionally dependent
on authentication. Authentication is a method of validating a
person as a legitimate user.
2.2.1.2.2 Audit
For most secure products, a capability must exist to audit
the security relevant events. As each user performs security
relevant tasks, the product must record the user identifier,
the action performed, and the result in a security log. For
CS1 compliant products, a capability is specified to allow a
system administrator to access and evaluate audit informa-
tion. This capability provides a method of protection in the
sense that security relevant events that occur within a com-
puter system can be logged and the responsible user held ac-
countable for his/her actions. Audit trails are used to detect
and deter penetration of a computer system and to reveal ac-
tivity that identifies misuse.
CS1 provides for an effective audit mechanism by supporting
the following basic security characteristics. It provides the
ability to:
o review the use of I&A mechanisms;
o discover the introduction of objects into a user's
address space;
o discover the deletion of objects; and
o discover actions taken by computer operators and sys-
tem administrators.
2.2.1.3 Assurance
Assurance addresses threats and vulnerabilities that can
affect the product during its development and it addresses
evaluation assurance. Assurance Package T1 was selected for
the CS1 level. This minimal assurance level is intended to
include most commercial computer products that incorporate
protection components today. Minimal assurance refers to the
fact that this package includes the lowest levels of develop-
ment and evaluation assurance components and only those com-
ponents deemed important to provide the necessary minimal
understanding of the product.
The intent of the product development assurance for this
package is to establish that the external behavior of the
product conforms to its user level and administrative docu-
mentation without any analysis of the internal structure of
the product's TCB. For this reason, only the claimed TCB pro-
tection properties, TCB interface description, and TCB ele-
ment list are required to enable security functional testing.
The intent of the operational support assurance for this
package is to establish a minimal level of user and adminis-
trative guidance and product information that enables the cor-
rect product installation, use of product security features,
and remediation of flaws.
The development evidence is commensurate with the assuranc-
es required. The intent is to require the type of assurance
evidence that is generated during the normal commercial de-
velopment process.
Evaluation support assurance establishes that the product,
and the context in which it is developed and supported, is
commensurate with the development assurance requirements. At
the T1 level, testing analysis and the requirement for inde-
pendent testing determines whether the product minimally
meets the functional protection requirements. Operational
support evaluation assurance determines whether the product
documentation correctly describes the security relevant oper-
ations.
2.2.2 Intended Method of Use
All individual users (both administrative and non-adminis-
trative) are assigned a unique user identifier. This user
identifier supports individual accountability and access con-
trol. The operating system authenticates the claimed identity
of the user before allowing the user to perform any further
actions.
A CS1 compliant product imposes controls on authorized us-
ers and on processes acting on their behalf to prevent users
from gaining access to information and other resources for
which they are not authorized. The product provides the capa-
bility for users to allow or disallow to other users access
to objects under their control. The objects are files that may
be read or written to or programs which may be executed. The
granularity of control is to the level of individual users
(although groups made up of individual users may be specified)
and individual objects. CS1 access controls permit the grant-
ing and revoking of access to be left to the discretion of the
individual users.
Products that comply with CS1 specifications are intended
to be used within the following operational constraints:
o The information system is designed to be administered
as a unique entity by a single organization.
o The information system is designed to manage comput-
ing, storage, input/output, and to control the sharing
of resources among multiple users and computer pro-
cesses.
o The administrative and non-administrative users are
identified as distinct individuals.
o The granting and revoking of access control permis-
sions are left to the discretion of individual users.
o The information system provides facilities for real-
time interaction with users that have access to input/
output devices.
2.2.3 Environmental Assumptions
A product designed to meet the CS1 Protection Profile is
intended to be a general purpose, multi-user operating system
that runs on either a workstation, minicomputer, or mainframe.
CS1 compliant products are expected to be used in commercial
and government environments. For government environments, CS1
conforms to the TCSEC C2 class of trust [1].The information
being processed may be unclassified, sensitive-but-unclassi-
fied, or single-level classified, but not multi-level classi-
fied information.
The following specific environmental conditions have been
assumed in specifying CS1:
o The product hardware base (e.g., CPU, printers, ter-
minals, etc.), firmware, and software will be pro-
tected from unauthorized physical access.
o There will be one or more personnel assigned to manage
the product including the security of the information
it contains.
o The operational environment will be managed according
to the operational environment documentation that is
required in the assurance chapter of the Protection
Profile.
o The IT product provides a cooperative environment for
users to accomplish some task or group of tasks.
o The processing resources of the IT product, including
all terminals, are assumed to be located within user
spaces that have physical access controls established.
2.2.4 Expected Threats
In general, the choice of which Protection Profile to
choose depends upon the level of security that is required for
that particular organizational environment. The lowest level,
the CS1 level, is intended for those commercial and government
environments where all the system personnel are trusted and
all the data on the system is at the same classification lev-
el. For example, a government agency where all personnel has
a government clearance, all data is unclassified, and there
is no outside network connections would be an ideal candidate
for CS1, i.e., the threats to be countered are such that only
a minimal level of trust is needed. However, most commercial
and government environments are more complex and require a
higher degree of trust. CS2 addresses the security needs for
the mainstream commercial and government environments. It
provides a higher level of trust for those organizations that
need to enforce a security policy where there is no need for
different classifications of data. CS3 is intended to provide
the highest level of trust for commercial and government en-
vironments. It is intended to be used in those environments
where a great deal of trust is required, such as in law en-
forcement agencies, nuclear facilities, or commercial air-
ports. It provides the strongest features, mechanisms, and
assurances to counter these threats.
A product that is designed to meet the CS1 Protection Pro-
file and operate within its assumed environment will provide
capabilities to counter threats. It should be noted, however,
that although a product may faithfully implement all the fea-
tures and assurances specified in this Protection Profile, the
complete elimination of any one threat should not be assumed.
The following threats have been assumed in specifying this
CS1 Protection Profile:
1. AN UNAUTHORIZED USER MAY ATTEMPT TO GAIN ACCESS TO THE
SYSTEM
For CS1 compliant products, the threat of an unauthorized
user gaining access to the system is primarily addressed by
I&A. I&A features allow the TCB to verify the identity of in-
dividuals attempting to gain access to the system. This is
accomplished through the use of passwords.
Although not a direct countermeasure, auditing requirements
are specified at the CS1 level to provide the capability to
perform an after-the-fact analysis of unauthorized system en-
try and login attempts. This provides an opportunity for the
system administrators to take corrective actions, such as
strengthening existing user authentication methods or requir-
ing users to change their passwords.
2. AN AUTHORIZED USER MAY ATTEMPT TO GAIN ACCESS TO
RESOURCES WHEN THE USER IS NOT ALLOWED ACCESS
An authorized user can try to gain access to unauthorized
resources by assuming the user identifier of another user and
thus gaining their associated access rights. This is addressed
through the use of passwords.
Once an authorized user has gained access to the system,
the threat still remains for a user to gain access to resourc-
es when the user is not authorized. At the resource level, CS1
specifies access control features to mediate (i.e., distrib-
ute, review, and revoke) user access to a subset of resources.
The object reuse feature has been specified to ensure that
resource contents are cleared before they are reused. This re-
duces the vulnerability that the resource contents can be read
before it is overwritten.
3. SECURITY RELEVANT ACTIONS MAY NOT BE TRACEABLE TO THE
USER ASSOCIATED WITH THE EVENT
CS1 accountability and audit requirements are specified to
provide the capability to track security relevant actions per-
formed by users and link such actions, if possible, to the
responsible identifier. Audit mechanisms are responsible for
the monitoring and detecting of real or potential security vi-
olations or events. These audit events can include successful
or unsuccessful: I&A events, the introduction of objects into
a user's address space, the deletion of objects, and actions
taken by system administrators. Each audit record includes the
date, time, location, type of event, identity of the user and
object involved, and the success or failure of the event.
4. SECURITY BREACHES MAY OCCUR BECAUSE OF TCB PENETRATION
TCB protection is a fundamental capability of CS compliant
products. The security components and mechanisms described in
this Protection Profile depend upon the integrity of the TCB
and on the TCB being isolated and non-circumventable. CS1
specifies requirements for a common and basic set of security
features to protect the TCB from outside penetration.
This threat is also countered through product assurance.
TCB interface definition establishes the boundary between the
TCB and its internal users. Security functional testing es-
tablishes that these TCB definitions and properties satisfy
the requirements of this Protection Profile.
5. USERS MAY BE ABLE TO BYPASS THE SECURITY FEATURES OF
THE SYSTEM
This threat is countered by authentication, access control,
audit, TCB isolation, TCB non-circumventability, and refer-
ence mediation requirements. Authentication requirements pro-
tect authentication data from unauthorized users. Resource
access control requirements protect access control data.
Audit requirements provide for the logging of successful
and unsuccessful accesses to resources as well as for changes
made to the system security configuration and system software
in the event that the system security features have been by-
passed.
The CS1 specification for reference mediation protects the
integrity of the access control mechanism and the TCB's func-
tionality. Starting at CS1, requirements exist for TCB medi-
ation of user references to objects and to security relevant
services.
CS1-compliant products maintain a domain for its own exe-
cution to protect it from external interference and tampering.
Such requirements address TCB isolation and non-circumvent-
ability of TCB isolation functions.
This threat is also countered through product assurance.
The definition of TCB properties assures the consistency of
the TCB's behavior. The identification of TCB elements pro-
vides the set of elements that determine the protection char-
acteristics of a product. The TCB interface definition
establishes the boundary between the TCB and its internal us-
ers. Security functional testing establishes that these TCB
definitions and properties satisfy the requirements of this
Protection Profile, and provide evidence against users being
able to bypass the security features of the system.
CS1 Functionality
3. Introduction
This section provides detailed functionality requirements
that must be satisfied by an Commercial Security 1 (CS1)
compliant product. Note that all plain text are words taken
directly from the Federal Criteria [11]. Any assignments or
refinements made to the text in the Federal Criteria for this
Protection Profile are indicated by the use of bold italics.
A Protection Profile requirement is an assignment when it is
directly taken as stated from the Federal Criteria component
without change or when a binding is made to a Federal Criteria
threshold definition. A Protection Profile requirement is a
refinement when a Federal Criteria requirement is taken to a
lower level of abstraction. The characterization of
Protection Profile requirements as being either assignments
or refinements can be found at each component level.
This Protection Profile for CS1 utilizes the following
levels from the Federal Criteria. Note that not all the
components from the Federal Criteria are reflected in this
Protection Profile; there are no specific requirements for
those components that are not listed.
CS1 Functional Component Summary
.------------------------------------------------------.
| | Component | |
| Component Name | Code | Level |
|======================================================|
| Security Policy Support: |
|----------------------------------+-----------+-------|
| Identification & Authentication | I&A | 1 |
|----------------------------------+-----------+-------|
| Audit | AD | 1 |
|----------------------------------+-----------+-------|
| Access Control | AC | 1 |
|----------------------------------+-----------+-------|
| Reference Mediation | RM | 1 |
|----------------------------------+-----------+-------|
| TCB Protection | P | 1 |
|----------------------------------+-----------+-------|
| Self Checking | SC | 1 |
`------------------------------------------------------'
3.1 Identification & Authentication
All users of the product must be identified and
authenticated. A login process is established that the user
interacts with in order to provide the information necessary
for identification and authentication. The identification and
authentication process begins the user's interaction with the
target product. First, the user supplies a unique user
identifier to the TCB. Then, the user is asked by the TCB to
authenticate that claimed identity. The user identifier is
used for both access control and also for accountability.
Therefore, the proper maintenance and control of the
identification mechanism and the identification databases are
vital to product security. Once a user has supplied an
identifier to the TCB, the TCB must verify that the user
really corresponds to the claimed identifier. This is done by
the authentication mechanism as described by the following
requirements.
For the CS1 level, I&A-1 was assigned from the Federal
Criteria. This I&A component level has not been refined from
the Federal Criteria.
I&A-1 Minimal Identification and Authentication
1. The TCB shall require users to identify
themselves to it before beginning to perform any
other actions that the TCB is expected to mediate.
The TCB shall be able to enforce individual
accountability by providing the capability to
uniquely identify each individual user. The TCB
shall also provide the capability of associating
this identity with all auditable actions taken by
that individual.
2. The TCB shall use a protected mechanism (e.g.,
passwords) to authenticate the user's identity.
3. The TCB shall protect authentication data so
that it cannot be used by any unauthorized user.
3.2 Audit
Audit supports accountability by providing a trail of user
actions. Actions are associated with individual users for
security relevant events and are stored in an audit trail.
This audit trail can be examined to determine what happened
and what user was responsible for a security relevant event.
The audit trail data must be protected from unauthorized
access, modification, or destruction. In addition, the audit
trail data must be available in a useful and timely manner for
analysis.
Audit data is recorded from several sources (such as from
the TCB or a privileged application) to produce a complete
picture of a user's security relevant actions. Therefore,
audit data must be correlated across audit collection systems.
The mechanisms providing audit data recording must be
tailorable to each product's needs. Both the audit data itself
and the mechanisms to determine what audit data is recorded
are protected by privileges.
Once the audit data is recorded, it is analyzed and
reported. At the CS1 level, reports are generated on request.
For the CS1 level, AD-1 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
AD-1 - Minimal Audit
1. The TCB shall be able to create, maintain, and
protect from modification or unauthorized access
or destruction an audit trail of accesses to the
objects it protects. The audit data shall be
protected by the TCB so that read access to it is
limited to those who are authorized for audit
data.
2. The TCB shall be able to record the following
types of events:
- use of the identification and authentication
mechanisms;
- introduction of objects into a user's address
space (e.g., file open, program initiation), and
deletion of objects;
- actions taken by computer operators and system
administrators and/or system security officers.
3. For each recorded event, the audit record shall
identify: date and time of the event, user, type
of event, and success or failure of the event. For
identification/authentication events the origin of
request (e.g., terminal ID) shall be included in
the audit record. For events that introduce an
object into a user's address space and for object
deletion events the audit record shall include the
name and policy attributes of the object (e.g.,
object security level).
4. The system administrator shall be able to
selectively audit the actions of one or more users
based on individual identity and/or object policy
attributes (e.g., object security level).
3.3 Access Control
Once the user has been granted access, the question of which
objects that authenticated user may access still remains. The
requirements below describe these subject accesses to
objects.
For the CS1 level, AC-1 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
AC-1 Minimal Access Control
1. Definition of Access Control Attributes
The TCB shall define and protect access control
attributes for subjects and objects. Subject
attributes shall include named individuals or
defined groups or both. Object attributes shall
include defined access rights (e.g., read, write,
execute) that can be assigned to subject
attributes.
2. Administration of Access Control Attributes.
The TCB shall define and enforce rules for
assignment and modification of access control
attributes for subjects and objects. The effect of
these rules shall be that access permission to an
object by users not already possessing access
permission is assigned only by authorized users.
These rules shall allow authorized users to
specify and control sharing of objects by named
individuals or defined groups of individuals, or
by both, and shall provide controls to limit
propagation of access rights. These controls shall
be capable of including or excluding access to the
granularity of a single user.
If different rules of assignment and modification
of access control attributes apply to different
subjects and/or objects, the totality of these
rules shall be shown to support the defined
policy.
3. Authorization of Subject References to Objects
The TCB shall define and enforce authorization
rules for the mediation of subject references to
objects. These rules shall be based on the access
control attributes of subjects and objects. These
rules shall, either by explicit user action or by
default, provide that objects are protected from
unauthorized access.
The scope of the authorization rules shall include
a defined subset of the product's subjects and
objects and associated access control attributes.
The coverage of authorization rules shall specify
the types of objects and subjects to which these
rules apply. If different rules apply to different
subjects and objects, the totality of these rules
shall be shown to support the defined policy.
4. Subject and Object Creation and Destruction
The TCB shall control the creation and destruction
of subjects and objects. These controls shall
include object reuse. That is, all authorizations
to the information contained within a storage
object shall be revoked prior to initial
assignment, allocation or reallocation to a
subject from the TCB's pool of unused storage
objects; information, including encrypted
representations of information, produced by a
prior subjects' actions shall be unavailable to
any subject that obtains access to an object that
has been released back to the system.
3.4 Reference Mediation
Reference mediation, that is, the control by the TCB of
subject accesses to objects, must be ensured so that the users
can have faith in the TCB's access control decisions. Also,
users must be ensured that all access to security services are
mediated by the TCB.
For the CS1 level, RM-1 was assigned from the Federal
Criteria. No further refinements were made from the Federal
Criteria.
RM-1 Mediation of References to a Defined Subject/Object
Subset
1. The TCB shall mediate all references to
subjects, objects, resources, and services (e.g.,
TCB functions) described in the TCB
specifications. The mediation shall ensure that
all references are directed to the appropriate
security-policy functions.
2. Reference mediation shall include references to
the defined subset of subjects, objects, and
resources protected under the TCB security policy,
and to their policy attributes (e.g., access
rights, security and/or integrity levels, role
identifiers).
3. References issued by privileged subjects shall
be mediated in accordance with the policy
attributes defined for those subjects.
3.5 TCB Protection
TCB protection is a fundamental requirement for a secure
product. All of the security components and mechanisms that
have been described depend upon the integrity of the TCB and
on the TCB being isolated and non-circumventable. The TCB must
be resistant to outside penetration.
For the CS1 level, P-1 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
P-1 Basic TCB Isolation
The TCB shall maintain a domain for its own
execution that protects it from external
interference and tampering (e.g., by reading or
modification of its code and data structures). The
protection of the TCB shall provide TCB isolation
and noncircumventability of TCB isolation
functions as follows:
1. TCB Isolation requires that (1) the address
spaces of the TCB and those of unprivileged
subjects are separated such that users, or
unprivileged subjects operating on their behalf,
cannot read or modify TCB data structures or code,
(2) the transfers between TCB and non-TCB domains
are controlled such that arbitrary entry to or
return from the TCB are not possible; and (3) the
user or application parameters passed to the TCB
by addresses are validated with respect to the TCB
address space, and those passed by value are
validated with respect to the values expected by
the TCB.
2. Noncircumventability of TCB isolation
functions requires that the permission to objects
(and/or to non-TCB data) passed as parameters to
the TCB are validated with respect to the
permissions required by the TCB, and references to
TCB objects implementing TCB isolation functions
are mediated by the TCB.
3.6 TCB Self-Checking
Validating the correct operation of the TCB firmware and
hardware is an important aspect of guaranteeing the integrity
of the product. Hardware and software features that validate
the correct operation of the product will be delivered with
the product to ensure that the hardware and firmware are
installed properly and are in working order.
For the CS1 level, SC-1 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
SC-1 Minimal Self Checking
Hardware and/or software features shall be
provided that can be used to periodically validate
the correct operation of the on-site hardware and
firmware elements of the TCB.
CS1 Assurance
4. Introduction
This chapter provides the CS1 development and evaluation
assurance requirements package using the development and
evaluation assurance components defined in Volume I and the
package contained in Volume I, Appendix G of the Federal
Criteria. The structure of each assurance package follows that
of the assurance components (i.e., each package consists of
development process, operational support, development
environment, development evidence, and evaluation process
components).
Assurance Package T1
This minimal assurance level is intended to include most
commercial computer products that incorporate protection
components. Minimal assurance refers to the fact that this
package includes the lowest levels of development and
evaluation assurance components and only those components
deemed important to provide the necessary minimal
understanding of the product.
The intent of product development assurance for this
package is to establish that the external behavior of the
product conforms to its user level and administrative
documentation without any analysis of the internal structure
of the product's TCB. For this reason, only the claimed TCB
protection properties, TCB interface description, and TCB
element list are required to enable functional testing.
The intent of the operational support assurance for this
package is to establish a minimal level of user and
administrative guidance and product information that enables
the correct product installation, use of product security
features, and remediation of flaws.
The development evidence required for this package is
commensurate with the assurances required. The intent of this
package is to require the type of assurance evidence that is
generated during the normal commercial development process.
The intent of evaluation support assurance is to establish
that the product, and the context in which it is developed and
supported, is commensurate with the development assurance
requirements. At the T1 level, testing analysis and the
requirement for independent testing determines whether the
product minimally meets the functional protection
requirements. Operational support evaluation assurance
determines whether the product documentation correctly
describes the security relevant operations.
The following table summarizes the generic assurance
components that comprise the minimal development assurance
package (T1):
.
CS1 Assurance Package Summary
.---------------------------------------.
| Assurance Components | T1 |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-1 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-1 |
|--------------------------------+------|
| TCB Interface Definition | IF-1 |
|--------------------------------+------|
| TCB Modular Decomposition | ---- |
|--------------------------------+------|
| TCB Structuring Support | ---- |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | ---- |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-1 |
|--------------------------------+------|
| Trusted Generation | ---- |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | ---- |
|--------------------------------+------|
| Configuration Management | ---- |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP1 |
|--------------------------------+------|
| Product Development | EPD1 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Product Support | ---- |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-1 |
|--------------------------------+------|
| Independent Testing | IT-1 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | ---- |
|--------------------------------+------|
| Operational Support | ---- |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | ---- |
|--------------------------------+------|
| Implementation | ---- |
`---------------------------------------'
4.1 TCB Property Definition
The definition of TCB properties assures the consistency of
the TCB's behavior. It determines a baseline set of properties
that can be used by system developers and evaluators to assure
that the TCB satisfies the defined functional requirements.
For CS1, PD-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
PD-1 Property Description
The developer shall interpret the functional
requirements of the protection profile within the
product TCB. For each functional requirement, the
developer shall: (1) identify the TCB elements and
their TCB interfaces (if any) that implement that
requirement; (2) describe the operation of these
TCB elements, and (3) explain why the operation of
these elements is consistent with the functional
requirement.
4.2 TCB Element Identification
The identification of TCB elements (hardware, firmware,
software, code, and data structures) provides the set of
elements that determine the protection characteristics of a
product. All assurance methods rely on the correct
identification of TCB elements either directly or indirectly.
For CS1, ID-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
ID-1: TCB Element Identification
The developer shall identify the TCB elements
(i.e., software, hardware/firmware code and data
structures). Each element must be unambiguously
identified by its name, type, release, and version
number (if any).
4.3 TCB Interface Definition
The TCB interface establishes the boundary between the TCB
and its external users and application programs. It consists
of several components, such as command interfaces (i.e., user
oriented devices such as the keyboard and mouse), application
program interfaces (system calls), and machine/processor
interfaces (processor instructions).
For CS1, IF-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
IF-1: Interface Description
The developer shall describe all external (e.g.,
command, software, and I/O) administrative (i.e.,
privileged) and non-administrative interfaces to
the TCB. The description shall include those
components of the TCB that are implemented as
hardware and/or firmware if their properties are
visible at the TCB interface.
The developer shall identify all call conventions
(e.g., parameter order, call sequence
requirements) and exceptions signaled at the TCB
interface.
4.4 Developer Functional Testing
Functional testing establishes that the TCB interface
exhibits the properties necessary to satisfy the requirements
of the protection profile. It provides assurance that the TCB
satisfies at least its functional protection requirements.
For CS1, FT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
FT-1: Conformance Testing
The developer shall test the TCB interface to show
that all claimed protection functions work as
stated in the TCB interface description.
The developer shall correct all flaws discovered
by testing and shall retest the TCB until the
protection functions are shown to work as claimed.
4.5 User's Guidance
User's guidance is an operational support assurance
component that ensures that usage constraints assumed by the
protection profile are understood by the users of the product.
It is the primary means available for providing product users
with the necessary background and specific information on how
to correctly use the product's protection functionality.
For CS1, UG-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
UG-1: Users' Guide
The developer shall provide a User Guide which
describes all protection services provided and
enforced by the TCB. The User Guide shall describe
the interaction between these services and provide
examples of their use. The User Guide may be in the
form of a summary, chapter or manual. The User
Guide shall specifically describe user
responsibilities. These shall encompass any user
responsibilities identified in the protection
profile.
4.6 Administrative Guidance
Administrative guidance is an operation support assurance
component that ensures that the environmental constraints
assumed by the protection profile are understood by
administrative users and operators of the IT product. It is
the primary means available to the developer for providing to
administrators and operators detailed, accurate information
on how to configure and install the product, operate the IT
product is a secure manner, make effective use of the
product's privileges and protection mechanisms to control
access to administrative functions and data bases, and to
avoid pitfalls and improper use of the administrative
functions that would compromise the TCB and user security.
For CS1, AG-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
AG-1: Basic Administrative Guidance
The developer shall provide a Trusted Facility
Manual intended for the product administrators
that describes how to use the TCB security
services (e.g., Access Control, System Entry, or
Audit) to enforce a system security policy. The
Trusted Facility Manual shall include the
procedures for securely configuring, starting,
maintaining, and halting the TCB. The Trusted
Facility Manual shall explain how to analyze audit
data generated by the TCB to identify and document
user and administrator violations of this policy.
The Trusted Facility Manual shall explain the
privileges and functions of administrators. The
Trusted Facility Manual shall describe the
administrative interaction between security
services.
The Trusted Facility Manual shall be distinct from
User Guidance, and encompass any administrative
responsibilities identified in security
management.
4.7 Evidence of TCB Protection Properties
The documentation of the TCB protection properties includes
the definition of the functional component requirements,
their modeling (if any), and their interpretation within a
product's TCB. For each requirement of a protection profile,
a description, definition (an informal, descriptive
specification), or a formal specification of the TCB
components and their operation corresponding to the
requirement must be provided.
For CS1, EPP-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPP-1 Evidence of TCB Correspondence to the Functional
Requirements
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. The TCB properties, which
are defined by this correspondence, shall be
explained in this documentation.
4.8 Evidence of Product Development
Product development evidence consists of the TCB design
evidence including the documentation of the TCB interface, TCB
elements, TCB structure, TCB structuring support, and TCB
design disciplines. The TCB implementation evidence includes
TCB source code, and the processor hardware and firmware
specifications.
For CS1, EPD-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPD-1: Description Of The TCB External Interface
The developer shall provide an accurate
description of the functions, effects, exceptions
and error messages visible at the TCB interface.
The developer shall provide a list of the TCB
elements (hardware, software, and firmware).
4.9 Evidence of Functional Testing
Functional testing evidence includes the testing itself,
the test plans, and test documentation results. Test plans
consist of: the description definition or specification of the
test conditions; the test data, which consists of the test
environment set-up; the test parameters and expected
outcomes; and a description of the test coverage.
For CS1, EFT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EFT-1: Evidence of Conformance Testing
The developer shall provide evidence of the
functional testing that includes the test plan,
the test procedures, and the results of the
functional testing.
4.10 Test Analysis
Test analysis determines whether the product meets the
functional protection requirements defined in the protection
profile. Functional testing is based on operational product,
the TCB's functional properties, the product's operational
support guidance, and other producer's documentation as
defined by the development evidence requirements. Functional
test analysis is based on the achieved test results as
compared to the expected results derived from the development
evidence.
For CS1, TA-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
TA-1: Elementary Test Analysis
The evaluator shall assess whether the producer
has performed the activities defined in the
development assurance requirements of the
protection profile for functional testing and
whether the producer has documented these
activities as defined in the development evidence
requirements of the protection profile. The
evaluator shall analyze the results of the
producer's testing activities for completeness of
coverage and consistency of results. The evaluator
shall determine whether the product's protection
properties, as described in the product
documentation have been tested. The evaluator
shall assess testing results to determine whether
the product's TCB works as claimed.
4.11 Independent Testing
Independent testing determines whether the product's TCB
meets the functional protection requirements as defined in the
functionality chapter of this Protection Profile. Testing is
based on the operational product, the TCB's functional
properties, the product's operational support guidance, and
other producer's documentation as defined by the Development
Evidence requirements.
For CS1, IT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
IT-1: Elementary Independent Testing
A tester, independent of the producer or
evaluator, shall perform functional and elementary
penetration testing. This testing shall be based
on the product's user and administrative
documentation, and on relevant known penetration
flaws. Satisfactory completion consists of
demonstrating that all user-visible security
enforcing functions and security-relevant
functions work as described in the product's user
and administrative documentation and that no
discrepancies exist between the documentation and
the product. Test results of the producer shall be
confirmed by the results of independent testing.
The evaluator may selectively reconfirm any test
result.
If the independent testing is performed at beta-
test sites, the producer shall supply the beta-
test plan and the test results. The evaluator
shall review the scope and depth of beta testing
with respect to the required protection
functionality, and shall verify independence of
both the test sites and the producer's and beta-
test user's test results. The evaluator shall
confirm that the test environment of the beta-test
site(s) adequately represents the environment
specified in the protection profile.
COMMERCIAL SECURITY 2 (CS2)
CS2 compliant products provide protection beyond
those of the CS1 Protection Profile by providing for
the separation of administrative functions and
access controls based on groups and access control
lists (ACLs). Identification and authentication
mechanisms include support for a rigorous password
management program (if desired). System entry and
availability and recovery requirements are also
specified. Secure administrative tools are
included, audit mechanisms are expanded, and data
reduction tools are listed.
CS2 Functional Component Summary
.------------------------------------------------------.
| | Component | |
| Component Name | Code | Level |
|======================================================|
| Security Policy Support: |
|----------------------------------+-----------+-------|
| Identification & Authentication | I&A | 3 |
|----------------------------------+-----------+-------|
| System Entry | SE | 2 |
|----------------------------------+-----------+-------|
| Trusted Path | TP | 1 |
|----------------------------------+-----------+-------|
| Audit | AD | 3 |
|----------------------------------+-----------+-------|
| Access Control | AC | 2+ |
|----------------------------------+-----------+-------|
| Security Management | SM | 2 |
|----------------------------------+-----------+-------|
| Reference Mediation | RM | 1 |
|----------------------------------+-----------+-------|
| TCB Protection | P | 1 |
|----------------------------------+-----------+-------|
| Self Checking | SC | 2 |
|----------------------------------+-----------+-------|
| TCB Initialization & Recovery | TR | 2 |
|----------------------------------+-----------+-------|
| Privileged Operations | PO | 1 |
|----------------------------------+-----------+-------|
| Ease-of-Use | EU | 2 |
`------------------------------------------------------'
CS2 Assurance Package Summary
.---------------------------------------.
| Assurance Components | T2+ |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-2 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-1 |
|--------------------------------+------|
| TCB Modular Decomposition | ---- |
|--------------------------------+------|
| TCB Structuring Support | SP-1 |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | ---- |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-1 |
|--------------------------------+------|
| Flaw Remediation | FR-1 |
|--------------------------------+------|
| Trusted Generation | TG-2 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | ---- |
|--------------------------------+------|
| Configuration Management | ---- |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP2 |
|--------------------------------+------|
| Product Development | EPD1 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Product Support | EPS1 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-1 |
|--------------------------------+------|
| Independent Testing | IT-1 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | ---- |
|--------------------------------+------|
| Operational Support | OSR1 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | ---- |
|--------------------------------+------|
| Implementation | ---- |
`---------------------------------------'
CS2 Rationale
2.12 Introduction
As outlined in the Federal Criteria, this rationale
describes the protection philosophy, how the security
features are intended to be used, the assumptions about the
environment in which a compliant product is intended to
operate, the threats within that environment, and the security
features and assurances that counter these threats. At the CS2
level, the features used to counter threats and the strength
of the assurance evidence is enhanced over CS1 and is
indicated in the text through bold italics.
2.12.1 Protection Philosophy
Any discussion of protection necessarily starts from a
protection philosophy, i.e., what it really means to call the
product "secure." In general, products will control access to
information and other resources through the use of specific
security features so that only properly authorized
individuals or processes acting on their behalf will be
granted access. For CS1, three fundamental requirements are
derived for this statement of protection:
o Access authorization
o Accountability
o Assurance
The totality of the functionality that enforces the access
authorization and accountability protection philosophy is
comprised of the hardware, software, and firmware of the
Trusted Computing Base (TCB). CS2 requires the TCB to be self-
protecting and resistant to bypass so that it is effective at
countering identified threats. CS2 also requires effective
management of security attributes and configuration
parameters. The assurance protection philosophy is comprised
of the development process, operational support, development
evidence, and evaluation process assurances. Each of these are
explained below.
2.12.1.1 Access Authorization
The access authorization portion of the philosophy of
protection for this profile addresses subject and object
access mediation. For CS2 compliant products, access
authorization has been further refined to include system
entry, subject and object mediation based on Access Control
Lists (ACLs), and privileged operations.
2.12.1.1.1 System Entry
CS2 provides the capability for a system administrator to
establish, maintain, and protect information from
unauthorized access, and defines the identities of and
conditions under which users may gain entry into the system.
These system entry controls are based on user identification,
time, location, and method of entry.
2.12.1.1.2 Subject and Object Access Mediation
CS2 provides protected access to resources and objects. As
defined in the TCSEC and specified in this profile, access
control permits system users and the processes that represent
them to allow or disallow to other users access to objects
under their control:
Access control is "a means of restricting access to
objects based on the identity of subjects and/or
groups to which they belong. The controls are
discretionary in the sense that a subject with a
certain access permission is capable of passing
that permission (perhaps indirectly) on to any
other subject." [1]
These controls permit the granting and revoking of access
privileges to be left to the discretion of the individual
users. The creator of the object becomes, by default, the
owner of the object. The owner can grant access as well as
specify the mode of access (read, write, execute) to the
object.
ACLs are defined that can effectively specify, for each
named object, a list of user identifiers with their respective
modes of access (read, write, and execute) to that object.
ACLs allow for control of:
o objects
o access modes that protect these objects
o specific access permissions to be passed onto
identified authorized subjects.
CS2 also allows for the specification and maintenance of
groups. Groups are a convenient means of logically associating
user identifiers. Groups can be referenced when specifying
ACLs.
2.12.1.1.3 Privileges
CS2 supports and promotes the separation and use of
privileges. A privilege enables a subject to perform a
security relevant operation that, by default, is denied.
Privileges cover all security aspects of a product. CS2
compliant products have tightly controlled privilege
definitions as well as control over subjects that hold
privileges.
2.12.1.2 Accountability
The accountability portion of the philosophy of protection
for this profile addresses user Identification and
Authentication (I&A), requirements for security auditing, and
a Trusted Path between a user and the operating system. Each
of these are explained below.
2.12.1.2.1 Identification and Authentication
User identification is required to support access control
and security auditing. This includes the capability to
establish, maintain, and protect a unique identifier for each
authorized user. User identification is functionally
dependent on authentication. Authentication is a method of
validating a person as a legitimate user.
User authentication in most computer systems has been
provided primarily through the use of passwords. CS2 supports
a variety of password features that give the product a great
amount of flexibility in the generation of passwords, in
password security, password features, and password
administration. For most products, a great deal of confidence
is placed on maintaining the privacy of passwords belonging
to individuals. I&A prevents unauthorized individuals from
logging into the product, therefore, password management is
essential to secure product operations. The risk of losing a
password is addressed within CS2 through promoting the use of
stringent password management practices.
In addition, CS2 allows for stronger authentication
approaches. CS2 specifies that a unique identifier be
associated with each trusted subject such as print spoolers
and database management system services. It also requires the
TCB to maintain, protect, and display status information for
all active users and all enabled or disabled user identities
or accounts.
2.12.1.2.2 Audit
For most secure products, a capability must exist to audit
the security relevant events. As each user performs security
relevant tasks, the product must record the user identifier,
the action performed, and the result in a security log. For
CS2 compliant products, a capability is specified to allow an
system administrator to access and evaluate audit
information. This capability provides a method of protection
in the sense that security relevant events that occur within
a computer system can be logged and the responsible user held
accountable for his/her actions. Audit trails are used to
detect and deter penetration of a computer system and to
reveal activity that identifies misuse.
CS2 provides for an effective audit mechanism by supporting
the following basic security characteristics. It provides the
ability to:
o review the use of I&A mechanisms;
o discover the introduction of objects into a user's
address space;
o discover the deletion of objects;
o discover actions taken by computer operators and
system administrators;
o audit attempts to violate resource allocation limits;
o protect the audit data so that access to it is limited
to system administrators that are authorized to
examine audit information;
o discover the use of privileges, such as changing the
ownership of an object;
o have the audit mechanism act as a deterrent against
penetrators or hackers; and
o use audit reduction tools for assessing the damage
that may result in the event of a violation of the
implemented security policy. These tools have the
capability of selectively reviewing the actions of one
or more users or groups, actions performed on a
specific object or system resource, and actions
associated with specific access control attributes.
2.12.1.3 Assurance
Assurance addresses all areas of product development
assurance and evaluation assurance. Development assurance
addresses the development process, operational support, the
development environment, and the development evidence.
Development process assurance defines the additional efforts
that a developer must undertake to satisfy the assurance
objectives while creating the product. It specifies how the
TCB should be designed and supported by the implementation as
well as how it should be tested. Operational support assurance
defines the documentation of the security features for both
administrative and non-administrative users as well as
requirements for TCB flaw remediation and TCB generation.
Development environment assurance includes requirements for
defining the product's life cycle and specific features for
configuration management. Development evidence assurance
defines the TCB's protection properties, details the
requirements for product testing and analysis, and defines the
requirements for product support. Evaluation assurance
establishes that the product, and the context in which it is
developed and supported, is commensurate with the development
assurance requirements.
The T2+ Assurance Package was chosen for CS2. This package
is indicated as being TS2+ since an additional component was
included for flaw remediation and for a higher level for
trusted generation. This level is intended to include most
commercial computer products that are designed to satisfy
functional requirements. Although most development assurance
components are required at their lowest levels, the
requirements of several product development components are
extended to capture (1) specific TCB properties, and (2) a
rudimentary notion of support for product structure. The
operational support component is also extended to enable
systematic flaw discovery, tracking, and repair.
The intent of the product development assurance for this
package is to establish that the external behavior of the
product conforms to its user level and administrative
documentation without analysis of the internal structure of
the product TCB. For this reason, only the claimed TCB
protection properties and their informal models, TCB
interface description, and TCB element list are required to
enable functional and penetration testing. Support for TCB
structuring is limited to process isolation and separation of
the protection critical TCB elements from the protection non-
critical ones.
The intent of the operational support assurance for this
package is to establish a minimal level of user and
administrative guidance and product information that enables
the correct product installation, use of product security
features, and remediation of flaws. Similarly, the
development environment assurances are intended to provide a
minimal level of control over the product configuration and
production. This level of development environment assurance
is similar to that already present in most established
commercial development organizations.The development evidence
required for this package is commensurate with the assurances
required. The intent of this package is to require the type
of assurance evidence that is generated during the normal
commercial development process.
At the T2+ level, evaluation support assurance determines
whether the product meets the functional protection
requirements for testing analysis and independent testing.
Operational support evaluation assurance determines whether
the product documentation correctly describes the security
relevant operations.
Also for CS2, flaw remediation was included in this
assurance package. Flaw remediation is important for
commercial environments since it ensures that flaws (i.e,
deficiencies in a product that enables a user external to the
TCB to violate the functional requirements of a protection
profile) that are discovered by the product consumers will be
tracked, corrected, and disseminated to the affected
customers.
2.12.1.4 Intended Method of Use
All individual users (both administrative and non-
administrative users) are assigned a unique user
identifier.This user identifier supports individual
accountability and access control. The operating system
authenticates the claimed identity of the user before allowing
the user to perform any further actions.
Products that comply with the CS2 Protection Profile are
provided with the capability of assigning privileges to secure
functions. These privileges are used to control access to
user, password files, and audit trails. This capability is
particularly important to prevent a "privileged user" or
"superuser" from having a wide set of privileges when only a
subset is needed.
A CS1 compliant product imposes controls on authorized
users and on processes acting on their behalf to prevent users
from gaining access to information and other resources for
which they are not authorized. The product provides the
capability for users to allow or disallow to other users
access to objects under their control. The objects are files
that may be read or written to or programs which may be
executed. The granularity of control is to the level of
individual users (although groups made up of individual users
may be specified) and individual objects. CS1 access controls
permit the granting and revoking of access to be left to the
discretion of the individual users.
Products that comply with CS2 specifications are intended
to be used within the following operational constraints:
o The information system is designed to be administered
as a unique entity by a single organization.
o The information system is designed to manage
computing, storage, input/output, and to control the
sharing of resources among multiple users and computer
processes.
o The administrative and non-administrative users are
identified as distinct individuals.
o The granting and revoking of access control
permissions (read, write, execute, and deny) are left
to the discretion of individual users.
o The information system provides facilities for real-
time interaction with users that have access to input/
output devices.
2.12.2 Environmental Assumptions
A product designed to meet the CS2 Protection Profile is
intended to be a general purpose, multi-user operating system
that runs on either a workstation, minicomputer, or mainframe.
CS2 compliant products are expected to be used in both
commercial and government environments. The information being
processed may be unclassified, sensitive-but-unclassified, or
single-level classified, but not multi-level classified
information.
The following specific environmental conditions have been
assumed in specifying CS2:
o The product hardware base (e.g., CPU, printers,
terminals, etc.), firmware, and software will be
protected from unauthorized physical access.
o There will be one or more personnel assigned to manage
the product including the security of the information
it contains.
o The operational environment will be managed according
to the operational environment documentation that is
required in the assurance chapter of the Protection
Profile.
o The IT product provides a cooperative environment for
users to accomplish some task or group of tasks.
o The processing resources of the IT product, including
all terminals, are assumed to be located within user
spaces that have physical access controls established.
o The IT product provides facilities for some or all of
the authorized users to create programs that use an
Application Programming Interface (API) to enable them
to protect themselves and their objects from
unauthorized use.
o Fail-safe defaults are included for the access control
attributes for the defined subjects and objects for
the product.
2.12.3 Expected Threats
In general, the choice of which Protection Profile to
choose depends upon the level of security that is required for
that particular organizational environment. The lowest level,
the CS1 level, is intended for those commercial and government
environments where all the system personnel are trusted and
all the data on the system is at the same classification
level. For example, a government agency where all personnel
has a government clearance, all data is unclassified, and
there is no outside network connections would be an ideal
candidate for CS1, i.e., the threats to be countered are such
that only a minimal level of trust is needed. However, most
commercial and government environments are more complex and
require a higher degree of trust. CS2 addresses the security
needs for the main stream commercial and government
environments. It provides a higher level of trust for those
organizations that need to enforce a security policy where
there is no need for different classifications of data. CS3
is intended to provide the highest level of trust for
commercial and government environments. It is intended to be
used in those environments where a great deal of trust is
required, such as in law enforcement agencies, nuclear
facilities, or commercial airports. It provides the strongest
features, mechanisms, and assurances to counter these
threats.
A product that is designed to meet the CS2 Protection
Profile and operate within its assumed environment will
provide capabilities to counter these threats. It should be
noted, however, that although a product may faithfully
implement all the features and assurances specified in this
Protection Profile, the complete elimination of any one threat
should not be assumed. A product that is designed to meet the
CS2 Protection Profile is generally known to be more effective
at countering the threats than products that meet the CS1
Protection Profile. CS2 products counter all the CS1 threats,
and contain stronger features and more assurance evidence than
CS1 products. In addition to countering CS1 threats, CS2
compliant products provide protection capabilities to counter
four additional threats:
1. AN UNAUTHORIZED USER MAY ATTEMPT TO GAIN ACCESS TO THE
SYSTEM
For CS1 compliant products, the threat of an unauthorized
user gaining access to the system is primarily addressed by
I&A. I&A features allow the TCB to verify the identity of
individuals attempting to gain access to the system. This is
accomplished through the use of passwords.
Although not a direct countermeasure, auditing requirements
are specified at the CS1 level to provide the capability to
perform an after-the-fact analysis of unauthorized system
entry and login attempts. This provides an opportunity for the
system administrators to take corrective actions, such as
strengthening existing user authentication methods or
requiring users to change their passwords.
For CS2 compliant systems, the threat of an unauthorized
user gaining access to the system is primarily addressed by
stronger I&A features and system entry requirements.
CS2 specifies password requirements that promote a strong
organizational password management program. These
requirements specify that: null passwords cannot be used
during normal operations; passwords be stored in a one-way
encrypted form; the clear text representation of a password
be automatically suppressed; passwords have a minimum-length;
and that the system utilize a password complexity-checking
algorithm. An advisory capability is also provided to exclude
a list of customer-specified passwords. Such requirements
support the use of passwords that are effective against
password guessing. To further reduce the probability of a
password being guessed, requirements limit the number of
attempted login attempts that can be made by a user associated
with a specific user identifier. The probability of a single
password being guessed is further reduced by requirements for
password aging, by having limitations on password reuse, and
by allowing users to choose a password that is already
associated with another user identifier.
CS2 also allows for a password generating capability.
Because random passwords can be difficult to remember and
users are tempted to write them down, requirements are
specified for the generation of passwords that are easy to
remember (i.e., pronounceable). Additionally, an advisory
requirement is specified to allow users to choose from a list
of alternative passwords.
To minimize the threat that a password has been
compromised, a requirement exists to allow a user to change
the password. Because a password can be compromised by
observing the characters on a terminal screen as it is being
typed, there is a requirement to blot out the clear-text
representation of the password on the display device.
In addition, requirements are specified to display an
advisory warning message to all users prior to system logon
to discourage a would-be system penetrator from attempting an
unauthorized system entry. Such a message can also provide a
basis for subsequent prosecution. System entry requirements
also specify additional controls on identified and
authenticated users entering the system. Once a user is
authenticated, a check is made to determine if the user is
allowed further entry. System entry is granted only in
accordance with the authenticated user's access control
attributes. These conditions are in terms of a user's identity
and his/her membership in groups (if they exist). In addition,
CS2 specifies system entry requirements to display to an
authorized user, upon successful system entry, the date and
time, method of access or port of entry, and the number of
failed logon attempts since the last successful system entry
by that user identifier. These requirements provide a user
with the capability to detect attempted or successful system
penetrations. In addition, requirements are specified to lock
and terminate an interactive session after an administrator-
specified period of user inactivity, and also for the TCB to
appear to perform the entire user authentication procedure
even if the user identification entered is invalid. The TCB
also provides a protected mechanism to allow or deny system
entry based on specified ranges of time. Also, conditions for
system entry via dial-up lines are required to be specified.
I&A requirements are also enhanced over those of CS1 by
specifying requirements for the identification for each
trusted user, and by specifying requirements for system
administrators to disable a user's identity or account when
the number of unsuccessful logon attempts exceeds an
administrator specified threshold. This is intended to
mitigate the effectiveness of successive attacks of system
penetration.
2. AN AUTHORIZED USER MAY ATTEMPT TO GAIN ACCESS TO
RESOURCES WHEN THE USER IS NOT ALLOWED ACCESS
An authorized user can try to gain access to unauthorized
resources by assuming the user identifier of another user and
thus gaining their associated access rights. This is addressed
through the use of passwords.
Once an authorized user has gained access to the system,
the threat still remains for a user to gain access to
resources when the user is not authorized. At the resource
level, CS2 specifies access control features to mediate (i.e.,
distribute, review, and revoke) user access to a subset of
resources.
The object reuse feature has been specified to ensure that
resource contents are cleared before they are reused. This
reduces the vulnerability that the resource contents can be
read before it is overwritten.
To address the vulnerability associated with passwords, CS2
specifies password requirements that promote a strong
organizational password management program. Besides those
password requirements that address penetration threats from
unauthorized users, other password requirements have been
specified to counter the threat of an insider (authorized
user) attack. There are password requirements that specify
that passwords must always be stored in encrypted format and
that passwords can never be included in audit trail data.
Also, in the event that a user selects a password that is
already in use by another user, requirements disallow the
system from acknowledging the dual association.
In addition, CS2 specifies access control features to limit
the user identifiers that may change to another user
identifier that provides any additional privileges to that
user. These controls are based on the user identifier and the
mode of access (i.e., read, write, and execute). Also,
administrators are provided with capabilities through the use
of protected mechanisms to set and control security related
parameters, defaults, thresholds, attributes, and other
security related data. This provides the ability to
effectively specify and control access to resources based on
site specific protection policies.
CS2 also specifies that privileges must be associated with
TCB functions, TCB calls, and accesses to privileged TCB
objects (e.g., user and group registration files. password
files, audit log files).
CS2 specifies requirements for a direct communication
channel, i.e., a trusted path, between the user and the
operating system to counter spoofing threats. This security
feature provides confidence that a user at a terminal will
communicate directly with the TCB rather than to malicious
code. In particular, to counter the threat of an authorized
user creating a spoof of legitimate user identifier
authorization prompts, CS2 specifies requirements for a
direct communication path between the user and the
authentication system.
Requirements are also specified to display an advisory
warning message to all users prior to system logon to
discourage unauthorized system entry. Such a message can also
provide a basis for subsequent prosecution.
Once an authorized user has been identified and
authenticated, system entry control can help counter threats
of inadvertent, deliberate, and coerced entry performed in an
unauthorized manner by an authorized user. At the end of
system entry control, the user bears the access-control
attributes determined during the I&A process, provided that
the system entry conditions are satisfied. These conditions
can be specified in terms of a user's identity, group
membership, or mode of access.
CS2 also provides other security features. Application
programming interfaces are provided so that applications can
protect themselves and their objects from unauthorized use.
CS2 specifies lists of user identities authorized to enter the
system via dial-up lines. CS2 also specifies general
authentication facilities for use by application developers,
system administrators, and users for the protection of
resources.
3. SECURITY RELEVANT ACTIONS MAY NOT BE TRACEABLE TO THE
USER ASSOCIATED WITH THE EVENT
CS2 accountability and audit requirements are specified to
provide the capability to track security relevant actions
performed by users, and link such actions, if possible, to the
responsible identifier. Audit mechanisms are responsible for
the monitoring and detecting of real or potential security
violations or events. These audit events can include
successful or unsuccessful: I&A events, the introduction of
objects into a user's address space, the deletion of objects,
and actions taken by system administrators. Each audit record
includes the date, time, location, type of event, identity of
the user and object involved, and the success or failure of
the event.
Requirements are specified to protect audit trail data and
the audit control mechanism from unauthorized access,
modification, or destruction. Audit features are specified to
provide post-collection audit analysis on specific data
items, users, and privileged operations. Also, a capability
is provided for trusted application programs to append data
to the security audit trail.
System entry control helps to enhance accountability by
providing a time, space, and mode-of-entry context to each
action for which the user is held accountable. These added
constraints help to give additional assurance that the proper
user is held responsible for a set of authorized actions.
At the CS2 level, tools are specified to enhance the
effectiveness of user accountability. CS3 specifies
requirements to provide tools to verify the consistency of the
audit trial data and the selection of audit events. Tools are
also specified for post-collection analysis to selectively
review various actions.
4. THE PRODUCT MAY BE DELIVERED, INSTALLED, AND THEN USED
IN AN UNSECURED MANNER
This threat is countered by explicitly requiring that the
product be delivered with all security features turned on.
This ensures that the product is secure by default rather than
insecure by default. This is complemented by allowing many
security features to be configurable so that, as a specific
organization gains experience with the actual threats in its
environment, the organization can adjust the degree of
security in their system. There are several requirements that
reinforce the "security by default" perspective during
initial installation. Requirements for security
administrative documentation are specified to increase the
likelihood that the administrator will install and start the
system in a secure manner.
5. SECURITY BREACHES MAY OCCUR BECAUSE AVAILABLE SECURITY
FEATURES ARE NOT USED OR ARE USED IMPROPERLY
Requirements for authentication, system and access control,
security management, and product documentation provide a
basis for countering this threat. Authentication requirements
provide for password management procedures to reduce the
possibility of easy to guess passwords and to initialize
passwords for users. Password generation algorithms are
provided that generate easy to remember passwords and that
give the user a choice of passwords. In addition, CS2 provides
for a capability to import and export objects and subjects
with defined access control attributes. This ensures that
access control attributes are maintained with the subject or
object during import and export operations.
Security management requirements are specified for listing,
setting, and updating all of the system security parameters
and attributes. These parameters and attributes pertain to
identification, authentication, system entry, access control,
audit trail analysis and availability features for the system
and for individual users. This allows a system administrator
to confirm that the system is properly configured and, if
necessary, to modify the existing configuration and
attributes. In addition, security management requirements
provide for routine control and maintenance of system
resources.
Product documentation requirements for users and
administrators describe how to perform security relevant
functions in a secure manner.
6. SECURITY BREACHES MAY OCCUR BECAUSE OF TCB PENETRATION
TCB protection is a fundamental capability of CS compliant
products. The security components and mechanisms described in
this Protection Profile depend upon the integrity of the TCB
and on the TCB being isolated and non-circumventable. CS1
specifies requirements for a common and basic set of security
features to protect the TCB from outside penetration.
This threat is also countered through product assurance.
The TCB interface definition establishes the boundary between
the TCB and its internal users. Security functional testing
establishes that these TCB definitions and properties satisfy
the requirements of the Protection Profile.
7. USERS MAY BE ABLE TO BYPASS THE SECURITY FEATURES OF
THE SYSTEM
This threat is countered by authentication, access control,
audit, TCB isolation, TCB non-circumventability, and
reference mediation requirements. Authentication requirements
protect authentication data from unauthorized users. Resource
access control requirements protect access control data.
Audit requirements provide for the logging of successful
and unsuccessful accesses to resources as well as for changes
made to the system security configuration and system software
in the event that the system security features have been
bypassed.
CS1 specifications for reference mediation protects the
integrity of the access control mechanism and the TCB's
functionality. Starting at CS1, requirements exist for TCB
mediation of user references to objects and to security
relevant services.
CS1-compliant products maintain a domain for its own
execution to protect it from external interference and
tampering. Such requirements address TCB isolation and non-
circumventability of TCB isolation functions.
This threat is also countered through product assurance.
The definition of TCB properties assures the consistency of
the TCB's behavior. The identification of TCB elements
provides the set of elements that determine the protection
characteristics of a product. The TCB interface definition
establishes the boundary between the TCB and its internal
users. Security functional testing establishes that these TCB
definitions and properties satisfy the requirements of this
Protection Profile, and provide evidence against users being
able to bypass the security features of the system. At the CS2
level, procedures also have to be established for developers
to accept customer reports of protection problems and requests
for corrections to those problems. Also, when the product is
delivered, all security related parameters must be set to its
fail-safe defaults.
8. SUBJECTS MAY BE DENIED CONTINUED ACCESSIBILITY TO THE
RESOURCES OF THE SYSTEM (I.E., DENIAL OF SERVICE)
Reliability of service requirements promote the continued
accessibility of system resources by authorized subjects.
These requirements principally counter threats related to
intentional or unintentional denial of service attacks. The
requirements include detecting and reporting facilities,
controls to limit systematically the disabling of user
identifiers, mechanisms for recovery in the event of a system
crash, resource quotas, and data backup and restoration. In
particular, mechanisms are specified for recovery and system
start-up, and for a maintenance mode of operation.
CS2 compliant systems provide the capability to detect and
recover from discontinuity of service using some combination
of automatic and procedural techniques. This capability is
intended to counter the threat that subjects may be denied
continued accessibility to the resources of the system (i.e.,
denial of service). Also, users are notified in advance to
change their password, so that access to the system is not
denied without warning. An advisory capability exists to allow
an system administrator to use null passwords during system
start-up. This allows a system administrator to access the
system even if the password mechanism has been compromised.
In addition, audit trails are compressed to avoid excessive
consumption of disk space.
9. THE INTEGRITY OF THE SYSTEM MAY BE COMPROMISED
At the CS2 level, requirements are specified for TCB
recovery and start-up to promote the secure state of the
system in the event of a system failure or discontinuity of
service. These features are intended to minimize the
likelihood of the loss of user objects during system recovery.
To protect audit trail data, a mechanism is specified to
automatically copy the audit trail file to an alternative
storage area.
CS2 compliant products also provide the capability to
validate the correct operation of the TCB software, firmware,
and hardware. Such features are important to ensure that the
software, hardware, and firmware are in working order.
CS2 Functionality
3. Introduction
This section provides detailed functionality requirements
that must be satisfied by a Commercial Security 2 (CS2)
compliant product. Note that all plain text are words taken
directly from the Federal Criteria. Any assignments or
refinements made to the text in the Federal Criteria's are
indicated by bold italics. A Protection Profile requirement
is an assignment when it is directly taken as stated from the
Federal Criteria component without change or when a binding
is made to a Federal Criteria threshold definition. A
Protection Profile requirement is a refinement when the
Federal Criteria requirement is taken to a lower level of
abstraction. The characterization of Protection Profile
requirements as being either assignments or refinements can
be found at each component level. Also, note that, unlike the
Federal Criteria, there are some items that are considered to
be "advisory," i.e., an item marked advisory is a desirable
feature but is not required for that component. Each advisory
item is marked with an "(A)".
This Protection Profile for CS2 utilizes the following
levels from the Federal Criteria. Note that not all the
components from the Federal Criteria are reflected in this
Protection Profile; there are no specific requirements for
those components that are not listed. Also note that a "+"
after the component level number indicates that a requirement
was included from a higher level of that component.
CS2 Functional Component Summary
.------------------------------------------------------.
| | Component | |
| Component Name | Code | Level |
|======================================================|
| Security Policy Support: |
|----------------------------------+-----------+-------|
| Identification & Authentication | I&A | 3 |
|----------------------------------+-----------+-------|
| System Entry | SE | 2 |
|----------------------------------+-----------+-------|
| Trusted Path | TP | 1 |
|----------------------------------+-----------+-------|
| Audit | AD | 3 |
|----------------------------------+-----------+-------|
| Access Control | AC | 2+ |
|----------------------------------+-----------+-------|
| Security Management | SM | 2 |
|----------------------------------+-----------+-------|
| Reference Mediation | RM | 1 |
|----------------------------------+-----------+-------|
| TCB Protection | P | 1 |
|----------------------------------+-----------+-------|
| Self Checking | SC | 2 |
|----------------------------------+-----------+-------|
| TCB Initialization & Recovery | TR | 2 |
|----------------------------------+-----------+-------|
| Privileged Operations | PO | 1 |
|----------------------------------+-----------+-------|
| Ease-of-Use | EU | 2 |
`------------------------------------------------------'
3.1 Identification & Authentication
All users of the product must be identified and
authenticated. A login process is established that interacts
with the user in order to provide the information necessary
for identification and authentication. The identification and
authentication process begins the user's interaction with the
target product. First, the user supplies a unique user
identifier to the TCB. Then, the user is asked to authenticate
that claimed identity by the TCB. The user identifier is used
for both access control and also for accountability.
Therefore, the proper maintenance and control of the
identification mechanism and the identification databases are
vital to TCB security. Once a user has supplied an identifier
to the TCB, the TCB must verify that the user really
corresponds to the claimed identifier. This is done by the
authentication mechanism as described by the following
requirements.
For the CS2 level, I&A-3 was assigned from the Federal
Criteria. This I&A component level has been refined from the
Federal Criteria by requiring that only system administrators
perform certain actions. Password requirements have also been
refined to reflect the importance of this protected mechanism
to commercial products. An additional refinement was made
regarding invalid user identification on error feedback.
Assignments were made for default thresholds for the number
of login attempts and login time intervals.
I&A-3 Exception-Controlled Identification and
Authentication
1. The TCB shall require users to identify
themselves to it before beginning to perform any
other actions that the TCB is expected to mediate.
The TCB shall be able to enforce individual
accountability by providing the capability to
uniquely identify each individual user. The TCB
shall also provide the capability of associating
this identity with all auditable actions taken by
that individual.
2. The TCB shall maintain authentication data that
includes information for verifying the identity of
individual users (e.g., passwords) as well as
information for determining the product policy
attributes of individual users, i.e. groups. These
data shall be used by the TCB to authenticate the
user's identity and to ensure that the attributes
of subjects external to the TCB that may be
created to act on behalf of the individual user
satisfy the product policy. The control of user
identification data shall be limited to system
administrators, except that a user shall be
allowed to modify his/her own authentication data
within prescribed limits (e.g., changing his/her
own password).
3. The TCB shall protect authentication data so
that it cannot be used by any unauthorized user.
The TCB shall appear to perform the entire user
authentication procedure even if the user
identification entered is invalid. Error feedback
shall contain no information regarding which part
of the authentication information is incorrect.
The TCB shall end the attempted login session if
the user performs the authentication procedure
incorrectly for a number of successive times
(i.e., a threshold) specified by an authorized
system administrator. The default threshold shall
be three times. When the threshold is exceeded,
the TCB shall send an alarm message to the system
console and/or to the administrator's terminal,
log this event in the audit trail, and delay the
next login by an interval of time specified by the
authorized system administrator. The default time
interval shall be 60 seconds. The TCB shall
provide a protected mechanism to disable the user
identity or account when the threshold of
successive, unsuccessful login attempts is
violated more than a number of times specified by
the administrator. By default, this mechanism
shall be disabled (as it may cause unauthorized
denial of service).
4. The TCB shall have the capability to maintain,
protect, and display status information for all
active users (e.g., users currently logged on,
current policy attributes) and of all user
accounts (i.e., enabled or disabled user identity
or account).
5. Whenever passwords are used as a protection
mechanism, then, at a minimum:
a. The TCB shall not indicate to the user if he/she
has chosen a password already associated with
another user.
b. The TCB shall store passwords in a one-way
encrypted form.
(1) The TCB shall require privilege to access
encrypted passwords.
c. The TCB shall automatically suppress or fully
blot out the clear-text representation of the
password on the data entry/display device.
d. The TCB shall, by default, prohibit the use of
null passwords during normal operation.
(1) A capability, accessible only to an system
administrator, to allow null passwords during
non-normal operations, such as system start-
up, manual recovery, or maintenance mode, on a
per-user identifier or per-port basis may be
provided. (A)
e. The TCB shall provide a protected mechanism to
allow a user to change his or her password. This
mechanism shall require re-authentication of the
user identity.
(1) The TCB shall provide a protected mechanism to
set or initialize passwords for users. The use
of this mechanism shall be limited to system
administrators.
f. The TCB shall enforce password aging on a per-
user identifier or per-group basis (i.e., a user
shall be required to change his or her password
after a system-specifiable minimum time). The
default for all non-system administrators shall
be sixty days.
(1) The default for system administrator
identifiers shall be thirty days.
(2) After the password aging threshold has been
reached, the password shall no longer be
valid, except as provided in 5 g below.
The control of password aging shall be limited to
system administrators.
g. The TCB shall provide a protected mechanism to
notify users in advance of requiring them to
change their passwords. This can be done by
either:
(1) Notifying users a system-specifiable period
of time prior to their password expiring. The
default shall be seven days.
- or -
(2) Upon password expiration, notifying the user
but allowing a system-specifiable subsequent
number of additional logons prior to requiring
a new password. The default shall be two
additional logons.
The control of user password expiration defaults
shall be limited to system administrators.
h. Passwords shall not be reusable by the same user
identifier for a system-specifiable period of
time. The default shall be six months. The
control of password re-use shall be limited to
system administrators.
i. The TCB shall provide an algorithm for ensuring
the complexity of user-entered passwords that
meets the following requirements:
(1) Passwords shall meet a system-specifiable
minimum length requirement. The default
minimum length shall be eight characters.
(2) The password complexity-checking algorithm
shall be modifiable by the TCB. The default
algorithm shall require passwords to include
at least one alphabetic character, one numeric
character, and one special character.
(3) The TCB should provide a protected mechanism
that allows systems to specify a list of
excluded passwords (e.g., company acronyms,
common surnames). (A)
(a) The TCB should prevent users from selecting
a password that matches any of those on the
list of excluded passwords. (A)
The control of password complexity shall be limited
to system administrators.
j. If password generation algorithms are present,
they shall meet the following requirements:
(1) The password generation algorithm shall
generate passwords that are easy to remember
(i.e., pronounceable).
(2) The TCB should give the user a choice of
alternative passwords from which to choose.
(A)
(3) Passwords shall be reasonably resistant to
brute-force password guessing attacks.
(4) If the "alphabet" used by the password
generation algorithm consists of syllables
rather than characters, the security of the
password shall not depend on the secrecy of the
alphabet.
(5) The generated sequence of passwords shall have
the property of randomness (i.e., consecutive
instances shall be uncorrelated and the
sequences shall not display periodicity).
3.2 System Entry
Once a user is authenticated, a check is made to see if the
user is allowed to enter the product. The qualifying checks
for system entry at the SE-2 level can include time-of-day,
day-of-week, date, location of terminal, or means of access
(e.g., dial-up port).
For the CS2 level, SE-2 was assigned from the Federal
Criteria. This component has been refined from the Federal
Criteria by specifying a default advisory warning to be
displayed before user logon, by limiting the control of system
entry requirements to system administrators, and by further
limiting the use of protected mechanisms to system
administrators. Also, default values for terminal locking and
session termination and for user policy attributes were
assigned.
SE-2 Time and Location Based Entry Control
1. Prior to initiating the system login procedure,
the TCB shall display an advisory warning message
to the user regarding unauthorized use of the
system and the possible consequences of failure to
heed this warning.
a. The message shall be system-specifiable.
b. The TCB shall be able to display a message of up
to twenty lines in length.
c. The following message shall be displayed by
default:
"NOTICE: This is a private computer system.
All users of this system are subject to
having their activities audited. Anyone
using this system consents to such
auditing. All unauthorized entries or
activities revealed by this auditing can be
used as evidence and may lead to criminal
prosecution."
The control of system entry messages shall be
limited to system administrators.
2. Before system entry is granted to a user, the
identity of that user shall be authenticated by
the TCB. If the TCB is designed to support
multiple login sessions per user identity, the TCB
shall provide a protected mechanism to enable
limiting the number of login sessions per user
identity or account with a default of a single
login session. The control of this mechanism to
limit the number of login sessions shall be
limited to system administrators.
3. The TCB shall grant system entry only in
accordance with the authenticated user's policy
attributes. The system entry conditions shall be
expressed in terms of users' policy attributes,
i.e., user identity and membership to groups. If
no explicit system-entry conditions are defined,
the system-entry default shall be used (e.g., the
correct user authentication). The TCB shall
provide a protected mechanism to allow or deny
system entry based on specified ranges of time.
Entry conditions using these ranges shall be
specified using time-of-day, day-of-week, and
calendar dates. The control of system entry
conditions shall be limited to system
administrators.
The TCB shall provide a protected mechanism to
allow or deny system entry based on location or
port of entry. Conditions for system entry via
dial-up lines (e.g., lists of user identities
authorized to enter the system via dial-up lines),
if any, shall be specified.The control of these
mechanisms shall be limited to system
administrators.
4. The TCB shall provide a protected mechanism that
enables authorized administrators to display and
modify the policy attributes used in system-entry
control for each user. The conditions under which
an unprivileged user may display these attributes
shall be specified.
5. Upon a user's successful entry to the system,
the TCB shall display the following data to the
user and shall not remove them without user
intervention: (1) the date, time, means of access
and port of entry of the last successful entry to
the system; and (2) the number of successive,
unsuccessful attempts to access the system since
the last successful entry by the identified user.
6. The TCB shall either lock or terminate an
interactive session after an administrator-
specified interval of user inactivity. The default
value for the lock interval shall be five minutes.
The default value for session termination shall be
fifteen minutes.
3.3 Trusted Path
A Trusted Path ensures that users have direct, unencumbered
communication with the TCB. A Trusted Path may be required at
various times during a subject session and also may be
initiated by a user during a TCB interaction.
For the CS2 level, TP-1 was assigned from the Federal
Criteria. This level was refined by requiring that there be a
direct Trusted Path connection to the authentication
mechanism.
TP-1 Login Trusted Path
The TCB shall support a trusted communication path
between itself and the user for initial
identification and authentication. Communications
via this path shall be initiated exclusively by a
user.
a. The TCB shall provide a protected mechanism by
which a display device may force a direct
connection between the port to which it is
connected and the authentication mechanism.
3.4 Audit
Audit supports accountability by providing a trail of user
actions. Actions are associated with individual users for
security-relevant events and are stored in an audit trail.
This audit trail can be examined to determine what happened
and what user was responsible for a security relevant event.
The audit trail data must be protected from unauthorized
access, modification, or destruction. In addition, the audit
trail data must be available in a useful and timely manner for
analysis.
Audit data is recorded from several sources (such as the
TCB or privileged applications) to produce a complete picture
of a user's security relevant actions. Therefore, audit data
must be correlated across audit collection systems. The
mechanisms providing audit data recording must be tailorable
to each product's needs. Both the audit data itself and the
mechanisms to determine what audit data is recorded are
protected by privileges. Once the audit data is recorded, it
is analyzed and reported. At the CS2 level, reporting can be
generated on request.
For the CS2 level, AD-4 was assigned from the Federal
Criteria. This level was refined from the Federal Criteria by
specifying that: password character strings not be recorded
in the audit trail; privileged applications be allowed to
append data to the audit trail; audit trail files be copied
to an alternative storage area after a system-specifiable
period of time; the TCB provide a protected mechanism for the
automatic deletion of security audit trail files. Assignments
were made to subject to object access control rules so that
they include user access to disk files, tape volumes, and tape
files.
AD-3 Audit Tools
1. The TCB shall be able to create, maintain, and
protect from modification or unauthorized access
or destruction an audit trail of accesses to the
objects it protects. The audit data shall be
protected by the TCB so that read access to it is
limited to those who are authorized for audit
data.
The TCB shall support an application program
interface that allows a privileged application to
append data to the security audit trail or to an
applications-specified alternative security audit
trail.
The TCB should support an option to maintain the
security audit trail data in encrypted format. (A)
2. The TCB shall be able to record the following
types of events:
- use of the identification and authentication
mechanisms, and system entry events;
- access control events selectable on a per
user, per subject, per object, per group, and/or
per policy attribute basis; i.e., introduction of
objects into a user's address space (e.g., file
open, program initiation), creation and deletion
of subjects and objects; distribution and
revocation of access rights; changes of subject
and object policy attributes; acquisition and
deletion of system privileges.
-actions taken by computer operators and system
administrators and/or system security officers;
i.e., privileged operations such as the
modification of TCB elements; accesses to TCB
objects (at a minimum, access to an object shall
include disk file access, tape volume, or tape
file access); changes of policy attributes of
users, TCB configuration and security
characteristics, and system privileges; selection
and modification of audited events.
The events that are auditable by default, and
those that are required for successful auditing of
other events, which may not be disabled, shall be
defined. The TCB shall provide a protected
mechanism that displays the currently selected
events and their defaults. The use of this
mechanism shall be restricted to authorized system
administrators.
3. For each recorded event, the audit record shall
identify: date and time of the event, user, type
of event, and success or failure of the event. For
identification/authentication events the origin of
request (e.g., terminal ID) shall be included in
the audit record. For events that introduce an
object into a user's address space and for object
deletion events the audit record shall include the
name and policy attributes of the object.
The character strings input as a response to a
password prompt shall not be recorded in the
security audit trail.
4. The TCB shall provide a protected mechanism to
turn auditing on and off, and to select and change
the events to be audited and their defaults,
during the system operation. The use of this
mechanism shall be restricted to authorized system
administrators. The system administrator shall be
able to selectively audit the actions of one or
more users based on individual identity and/or
object policy attributes. Audit review tools shall
be available to authorized system administrators
to assist in the inspection and review of audit
data, and shall be protected from unauthorized
use, modification, or destruction.
The TCB shall provide tools for audit data
processing. These shall include specifically
designed tools: for verifying the consistency of
the audit data; for verifying the selection of
audit events; for audit trail management. The
audit trail management tools shall enable:
- creation, destruction, and emptying of audit
trails; use of warning points regarding the size
of the audit data, and modification of the audit
trail size;
-formatting and compressing of event records;
-displaying of formatted audit trail data; and
-maintaining the consistency of the audit trail
data after system failures and discontinuity of
operation.
The TCB shall provide a protected mechanism for
the automatic copying of security audit trail
files to an alternative storage area after a
system-specifiable period of time.
The TCB shall provide a protected mechanism for
the automatic deletion of security audit trail
files after a system-specifiable period of time.
The default shall be thirty days.
(a) It shall not be possible to delete the
security audit trail before it gets copied
to an alternate storage area.
(b) It shall be possible to disable this mechanism.
The use of audit trail management functions shall
be limited to system administrators.
5. Audit review tools shall be available to
authorized users to assist in the inspection and
review of audit data, and shall be protected from
unauthorized modification or destruction. The TCB
shall also provide tools for post-collection audit
analysis (e.g., intrusion detection) that shall be
able to selectively review (1) the actions of one
or more users (e.g., identification,
authentication, system-entry, and access control
actions); (2) the actions performed on a specific
object or system resource; and (3) all, or a
specified set of, audited exceptions; and (4)
actions associated with a specific policy
attributes. The review tools shall be able to
operate concurrently with the system operation.
3.5 Access Control
Once the user has been granted access, the question of which
objects that authenticated user may access still remains. An
owner, or an authorized user, allows or denies to other users
access to that object. The requirements below describe subject
accesses to objects.
For the CS2 level, AC-2+ was assigned from the Federal
Criteria. This level is indicated as being AC-2+ because a
requirement was included from level AC-4 (the distribution,
revocation, and review of access control attributes rules).
This is indicated in the text by an "[AC-4]" in front of the
requirement.This component level was refined from the Federal
Criteria by specifying: a protected mechanism for groups; a
limitation on the changes an active subject can make to a
privileged user identifier; a definition of an access control
list; and minimum authorization rules.
AC-2+ Basic Access Control
1. Definition of Access Control Attributes
The TCB shall define and protect access control
attributes for subjects and objects. Subject
attributes shall include named individuals or
defined groups or both. Object attributes shall
include defined access rights (i.e., read, write,
execute) that can be assigned to subject
attributes.
The TCB shall be able to assign access rights to
group identities.
If multiple access control policies are supported,
the access control attributes corresponding to
each individual policy shall be identified.
The subject and/or object attributes shall
accurately reflect the sensitivity and integrity
of the subject or object.
2. Administration of Access Control Attributes
The TCB shall define and enforce rules for
assignment and modification of access control
attributes for subjects and objects.
The TCB shall provide a protected mechanism for
groups as follows:
a. A user identifier shall be able to be associated
with one or more groups.
b. The TCB shall provide a protected mechanism to
list the names of all groups.
c. The TCB shall provide a protected mechanism to
list the membership of any group.
Rules for maintaining group membership shall be
provided. These rules shall include those for
displaying and modifying the list of users
belonging to a group and the group attributes of
those users.
The effect of these rules shall be that access
permission to an object by users not already
possessing access permission is assigned only by
authorized users.
Only the current owner or system administrators
shall modify access control attributes on objects.
(a) There should be a distinct access right to
modify the contents of an object's access
control list (e.g., an "ownership" or
"control" access right). (A)
The TCB shall provide a protected mechanism to
modify group membership. The use of this mechanism
shall be under the control of system
administrators. Authority to modify specific group
membership may be delegated.
The TCB shall provide a protected mechanism by which
the user identifier associated with a subject
attribute can be changed while the subject is
active. It shall also provide a protected mechanism
for limiting the user identifiers that may change
to a user identifier that would provide any
additional access rights. The control of these
mechanisms shall be limited to system
administrators.
[AC-4]: These rules shall allow authorized users
to specify and control sharing of objects by named
individuals or defined groups of individuals, or
by both, and shall provide controls to limit
propagation of access rights, (i.e., these rules
shall define the distribution, revocation, and
review of access control attributes). The controls
defined by these rules shall be capable of
specifying for each named object, a list of
individuals and a list of groups of named
individuals, with their respective access rights
to that object. Furthermore, for each named
object, it shall be possible to specify a list of
named individuals and a list of groups of named
individuals for which no access to the object is
given. These controls shall be capable of
including or excluding access to the granularity
of a single user.
The rules for assignment and modification of
access control attributes shall include those for
attribute assignment to objects during import and
export operations. If different rules of
assignment and modification of access control
attributes apply to different subjects and/or
objects, the totality of these rules shall be
shown to support the defined policy.
3. Authorization of Subject References to Objects
The TCB shall define and enforce authorization
rules for the mediation of subject references to
objects. These rules shall be based on the access
control attributes of subjects and objects. These
rules shall, either by explicit user action or by
default, provide that objects are protected from
unauthorized access.
For each object, the authorization rules of the TCB
shall be based on a protected mechanism to specify
a list of user identifiers or groups with their
specific access rights to that object (i.e., an
access control list).
At a minimum, the authorization rules shall be
defined as follows:
a. The access rights associated with a user
identifier shall take precedence over the access
rights associated with any groups of which that
user identifier is a member.
b. When a user identifier can be an active member of
multiple groups simultaneously, or if the access
rights associated with the user identifier
conflict with the access rights associated with
any group in which the user is a member, it shall
be possible for an system administrator to
configure rules that combine the access rights to
make a final access control decision.
c. The TCB shall provide a protected mechanism to
specify default access rights for user
identifiers not otherwise specified either
explicitly by a user identifier or implicitly by
group membership.
The scope of the authorization rules shall include
a defined subset of the product's subjects and
objects and associated access control attributes.
The coverage of authorization rules shall specify
the types of objects and subjects to which these
rules apply. If different rules apply to different
subjects and objects, the totality of these rules
shall be shown to support the defined policy.
If multiple policies are supported, the
authorization rules for each policy shall be
defined separately. The TCB shall define and
enforce the composition of policies, including the
enforcement of the authorization rules (e.g.,
subject and object type coverage, enforcement
precedence).
4. Subject and Object Creation and Destruction
The TCB shall control the creation and destruction
of subjects and objects. These controls shall
include object reuse. That is, all authorizations
to the information contained within a storage
object shall be revoked prior to initial
assignment, allocation or reallocation to a
subject from the TCB's pool of unused storage
objects; information, including encrypted
representations of information, produced by a
prior subjects' actions shall be unavailable to
any subject that obtains access to an object that
has been released back to the system.
3.6 Security Management
The management of security attributes and configuration
parameters is an important aspect of a secure product.
Mechanisms have to be provided to easily maintain the product,
and they must be protected so that only system administrators
can manage the security aspects of the product.
For the CS2 level, SM-2 was assigned from the Federal
Criteria. This level was refined from the Federal Criteria by
specifying that sessions be terminated rather than locked. An
assignment was made for the definition and maintenance of
groups as a security policy attribute.
SM-2 Basic Security Management
1. The TCB shall provide an installation mechanism
for the setting and updating of its configuration
parameters, and for the initialization of its
protection-relevant data structures before any
user or administrator policy attributes are
defined. It shall allow the configuration of TCB
internal databases and tables.
The TCB shall distinguish between normal mode of
operation and maintenance mode, and shall provide
a maintenance-mode mechanism for recovery and
system start-up.
2. The TCB shall provide protected mechanisms for
displaying and modifying the security policy
parameters. These parameters shall include
identification, authentication, system entry and
access control parameters for the entire system
and for individual users.
The TCB shall have a capability to define the
identification and authentication policy on a
system-wide basis (e.g., password minimum and
maximum lifetime, password length and complexity
parameters). The TCB mechanisms shall have the
capability to limit: (1) maximum period of
interactive session inactivity, (2) maximum login
or session time, and (3) successive unsuccessful
attempts to log in to the system. In particular,
the TCB shall provide a protected mechanism to
specify that sessions be terminated rather than
locked after a period of inactivity. The control
of these mechanisms shall be limited to system
administrators.
3. The TCB shall provide protected mechanisms for
manually displaying, modifying, or deleting user
registration and account parameters. These
parameters shall include unique user identifiers,
their account, and their associated user name and
affiliation. The TCB shall allow the manual
enabling and disabling of user identities and/or
accounts.
The TCB shall provide a means to uniquely identify
security policy attributes. It shall also provide
a means of listing all these attributes for a
user, and all the users associated with an
attribute. It shall be capable of defining and
maintaining the security policy attributes for
subjects including: defining and maintaining
privileges for privileged subjects, discretionary
(i.e., definition and maintenance of groups) and
non-discretionary attributes and centralized
distribution, review and revocation of policy
attributes.
4. The TCB shall provide protected mechanisms for
routine control and maintenance of system
resources. It shall allow the enabling and
disabling of peripheral devices, mounting of
removable storage media, backing-up and recovering
user objects; maintaining the TCB hardware and
software elements (e.g., on site testing); and
starting and shutting down the system.
5. The use of the protected mechanisms for system
administration shall be limited to authorized
administrative users. The control of access-
control attributes shall be limited to the object
owner and to system administrators.
3.7 Reference Mediation
Reference mediation, that is, the control by the TCB of
subject accesses to objects, must be ensured so that the users
can have faith in the TCB's access control decisions. Also,
users must be ensured that all access to security services are
mediated by the TCB.
For the CS2 level, RM-1 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
RM-1 Mediation of References to a Defined Subject/Object
Subset
1. The TCB shall mediate all references to
subjects, objects, resources, and services (e.g.,
TCB functions) described in the TCB
specifications. The mediation shall ensure that
all references are directed to the appropriate
security-policy functions.
2. Reference mediation shall include references to
the defined subset of subjects, objects, and
resources protected under the TCB security policy,
and to their policy attributes (e.g., access
rights, security and/or integrity levels, role
identifiers).
3. References issued by privileged subjects shall
be mediated in accordance with the policy
attributes defined for those subjects.
3.8 Logical TCB Protection
TCB protection is a fundamental requirement for a secure
product. All of the security components and mechanisms that
have been described depend upon the integrity of the TCB and
on the TCB being isolated and non-circumventable. The TCB must
be resistant to outside penetration.
For the CS2 level, P-1 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
P-1 Basic TCB Isolation
The TCB shall maintain a domain for its own
execution that protects it from external
interference and tampering (e.g., by reading or
modification of its code and data structures). The
protection of the TCB shall provide TCB isolation
and noncircumventability of TCB isolation
functions as follows:
1. TCB Isolation requires that (1) the address
spaces of the TCB and those of unprivileged
subjects are separated such that users, or
unprivileged subjects operating on their behalf,
cannot read or modify TCB data structures or code,
(2) the transfers between TCB and non-TCB domains
are controlled such that arbitrary entry to or
return from the TCB are not possible; and (3) the
user or application parameters passed to the TCB
by addresses are validated with respect to the TCB
address space, and those passed by value are
validated with respect to the values expected by
the TCB.
2. Noncircumventability of TCB isolation
functions requires that the permission to objects
(and/or to non-TCB data) passed as parameters to
the TCB are validated with respect to the
permissions required by the TCB, and references to
TCB objects implementing TCB isolation functions
are mediated by the TCB.
3.9 TCB Self-Checking
Validating the correct operation of the TCB firmware and
hardware is an important aspect of guaranteeing the integrity
of the product. Hardware and software features that validate
the correct operation of the product will be delivered with
the product to ensure that the hardware and firmware are
installed properly and are in working order.
For the CS2 level, SC-2 was assigned from the Federal
Criteria.The Federal Criteria was refined to limit the
execution of operator-controlled tests to system
administrators.
SC-2 Basic Self Checking
Hardware and/or software features shall be
provided that can be used to periodically validate
the correct operation of the on-site hardware and
firmware elements of the TCB. These features shall
include: power-on tests, loadable tests, and
operator-controlled tests.
The power-on tests shall test all basic components
of the TCB hardware and firmware elements
including memory boards and memory
interconnections; data paths; busses; control
logic and processor registers; disk adapters;
communication ports; system consoles, and the
keyboard speaker. These tests shall cover all
components that are necessary to run the loadable
tests and the operator-controlled tests.
The loadable tests shall cover: processor
components (e.g., arithmetic and logic unit,
floating point unit, instruction decode buffers,
interrupt controllers, register transfer bus,
address translation buffer, cache, and processor-
to-memory bus controller); backplane busses;
memory controllers; and writable control memory
for operator-controlled and remote system-
integrity testing.
Operator-controlled tests shall be able to
initiate a series of one-time or repeated tests,
to log the results of these tests and, if any fault
is detected, to direct the integrity-test programs
to identify and isolate the failure. The execution
of operator-controlled tests shall be limited to
system administrators.
3.10 TCB Initialization and Recovery
The recovery and start-up of the TCB must be ensured so that
the product always remains in a secure state, whether the
recovery is performed manually or automatically.
For the CS2 level, TR-1 was assigned from the Federal
Criteria. No further refinements were made from the Federal
Criteria.
TR-2 Basic for Recovery or Start-up
1. Procedures and/or mechanisms shall be provided
to assure that, after a TCB failure or other
discontinuity, recovery without protection
compromise is obtained.
2. If automated recovery and start-up is not
possible, the TCB shall enter a state where the
only system access method is via administrative
interfaces, terminals, or procedures.
Administrative procedures shall exist to restore
the system to a secure state (i.e., a state in
which all the security-policy properties hold).
3.11 Privileged Operation
Privileges are associated with functional components so
that at any given time only those operations that are
associated with the privilege can be performed. The privileges
that a product needs must be identified and must cover all the
security aspects of the product, including the secure
administration of the product, and should be defined so that
there is not a single privileged mode for all of the TCB's
operations.
For the CS2 level, PO-1 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
PO-1 Privilege Association with TCB Modules
1. TCB privileges needed by individual functions,
or groups of functions, shall be identified.
Privileged TCB calls or access to privileged TCB
objects, such as user and group registration
files, password files, security and integrity-
level definition file, role definition file, or
audit-log file shall also be identified.
2. The identified privileged functions of a TCB
functional component shall be associated only with
the privileges necessary to complete their task.
3.12 Ease-of-TCB-Use
If security mechanisms are not easy to use and maintain,
then administrative and non-system administrators may be
tempted to disable the security mechanisms. Therefore, ease
of use becomes an important element in the administration of
a secure product and in the creation of privileged
applications. It also minimizes errors on the part of both the
administrative and non-system administrators, and can serve
to minimize the consequences of these errors.
For the CS2 level, EU-2 was assigned from the Federal
Criteria. No refinements were made from the Federal Criteria.
EU-2 Ease of Application Programming
1. The TCB shall provide well-defined actions to
undertake administrative functions. Default
options shall be provided for security parameters
of administrative functions.
The TCB shall include fail-safe defaults for the
policy attributes of the defined subjects and
objects, as well as user-setable defaults for the
defined subjects and objects.
2. The TCB shall provide well-defined application
programming interfaces and programming functions
(e.g., libraries) for all its policies to support
the development of applications that can define
and enforce security policies on application-
controlled subjects and objects. The TCB shall
enable user-controlled reduction of access rights
available to applications.
CS2 Assurance
4. Introduction
This chapter provides the CS2 development and evaluation
assurance requirements package using the development and
evaluation assurance components defined in Volume I and the
package contained in Volume I, Appendix G of the Federal
Criteria. The structure of each assurance package follows that
of the assurance components (i.e., each package consists of
development process, operational support, development
environment, development evidence, and evaluation process
components).
Assurance Package T2+
Assurance package T2+ was chosen for CS2. This package is
indicated as being TS2+ since an additional component was
included for flaw remediation and a higher level was chosen
for trusted generation. This basic assurance level is intended
to include most commercial computer products that are designed
to satisfy functional requirements. Although most development
assurance components are required at their lowest levels, the
requirements of several product-development components are
extended to capture (1) specific TCB properties, and (2) a
rudimentary notion of support for product structure. The
operational support component is also extended to enable
systematic flaw discovery, tracking, and repair.
The intent of the product development assurance for this
package is to establish that the external behavior of the
product conforms to its user level and administrative
documentation without analysis of the internal structure of
the product TCB. For this reason, only the claimed TCB
protection properties and their informal models, TCB
interface description, and TCB element list are required to
enable functional testing. Support for TCB structuring is
limited to process isolation and separation of the protection
critical TCB elements from the protection non-critical ones.
The intent of the operational support assurance for this
package is to establish a minimal level of user and
administrative guidance and product information that enables
the correct product installation and use of product security
features. Similarly, the development environment assurances
are intended to provide the a minimal level of control over
the product configuration and production. This level of
development environment assurance is similar to that already
present in most established commercial development
organizations.
The development evidence required for this package is
commensurate with the assurances required. The intent of this
package is to require the type of assurance evidence that is
generated during the normal commercial development process.
The intent of evaluation support assurance is to establish
that the product, and the context in which it is developed and
supported, is commensurate with the development assurance
requirements. At the T2+ level, testing analysis and the
requirement for independent testing determines whether the
product meets the functional protection requirements.
Operational support evaluation assurance determines whether
the product documentation correctly describes the security
relevant operations.
Also for CS2, flaw remediation was included in this
package. Flaw remediation is important for commercial
environments since it ensures that flaws (i.e, deficiencies
in a product that enables a user external to the TCB to violate
the functional requirements of a protection profile) that are
discovered by the product consumers will be tracked,
corrected, and disseminated to the affected customers.
The following table summarizes the generic assurance
components that comprise the Basic Development Assurance
Package (T2+).
CS2 Assurance Package Summary
.---------------------------------------.
| Assurance Components | T2+ |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-2 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-1 |
|--------------------------------+------|
| TCB Modular Decomposition | ---- |
|--------------------------------+------|
| TCB Structuring Support | SP-1 |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | ---- |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-1 |
|--------------------------------+------|
| Flaw Remediation | FR-1 |
|--------------------------------+------|
| Trusted Generation | TG-2 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | ---- |
|--------------------------------+------|
| Configuration Management | ---- |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP2 |
|--------------------------------+------|
| Product Development | EPD1 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Product Support | EPS1 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-1 |
|--------------------------------+------|
| Independent Testing | IT-1 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | ---- |
|--------------------------------+------|
| Operational Support | OSR1 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | ---- |
|--------------------------------+------|
| Implementation | ---- |
`---------------------------------------'
4.1 TCB Property Definition
The definition of TCB properties assures the consistency of
the TCB's behavior. It determines a baseline set of properties
that can be used by system developers and evaluators to assure
that the TCB satisfies the defined functional requirements.
For CS2, PD-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
PD-2 Informal Property Identification
The developer shall provide informal models for
the functional components and sub-components of
the profile. At a minimum, an informal model of
the access control components shall be provided.
Each informal model shall include (abstract) data
structures and operations defining each functional
component or sub-component, and a description of
the model properties. The developer shall
interpret (e.g., trace) the informal models within
the product TCB. For each model entity, the
developer shall: (1) identify the TCB elements and
their TCB interfaces (if any) that implement that
entity; (2) define the operation of these TCB
elements, and (3) explain why the operation of
these elements is consistent with the model
properties. The developer's interpretation of each
informal model, which defines the TCB properties,
shall identify all TCB elements that do not
correspond to any model entity and shall explain
why these elements do not render the TCB
properties invalid.
For the components that are not informally
modeled, the developer shall interpret the
functional requirements of the protection profile
within the product TCB. For each functional
requirement, the developer shall: (1) identify the
TCB elements and their TCB interfaces (if any)
that implement that requirement; (2) describe the
operation of these TCB elements, and (3) explain
why the operation of these elements is consistent
with the functional requirement. The developer's
interpretation of each functional requirement,
which describes the TCB properties, shall identify
all TCB elements that do not correspond to any
functional requirement and shall explain why these
elements do not render the TCB properties invalid.
4.2 TCB Element Identification
The identification of TCB elements (hardware, firmware,
software, code, and data structures) provides the set of
elements that determine the protection characteristics of a
product. All assurance methods rely on the correct
identification of TCB elements either directly or indirectly.
For CS2, ID-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
ID-1: TCB Element Identification
The developer shall identify the TCB elements
(i.e., software, hardware/firmware code and data
structures). Each element must be unambiguously
identified by its name, type, release, and version
number (if any).
4.3 TCB Interface Definition
The TCB interface establishes the boundary between the TCB
and its external users and application programs. It consists
of several components, such as command interfaces (i.e., user
oriented devices such as the keyboard and mouse), application
program interfaces (system calls), and machine/processor
interfaces (processor instructions).
For CS2, IF-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
IF-1: Interface Description
The developer shall describe all external (e.g.,
command, software, and I/O) administrative (i.e.,
privileged) and non-administrative interfaces to
the TCB. The description shall include those
components of the TCB that are implemented as
hardware and/or firmware if their properties are
visible at the TCB interface.
The developer shall identify all call conventions
(e.g., parameter order, call sequence
requirements) and exceptions signaled at the TCB
interface.
4.4 TCB Structuring Support
Structuring the TCB into modules is necessary. However, the
modular decomposition does not necessarily reflect the run-
time enforcement of the TCB structuring since the separation
of modules may not necessarily be supported by run-time
mechanisms. The run-time enforcement of internal TCB
structuring adds a measure of assurance that the TCB elements
that are critical to the enforcement of the protection
functions are separate from the non-critical elements. Also,
the use of run-time enforcement of TCB structuring helps
separate protection-critical TCB elements from each other,
thereby helping to enforce the separation of protection
concerns and minimizing the common mechanisms shared between
protection critical elements.
For CS3, SP-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
SP-1: Process Isolation
The TCB shall maintain process isolation.
4.5 Developer Functional Testing
Functional testing establishes that the TCB interface
exhibits the properties necessary to satisfy the requirements
of the protection profile. It provides assurance that the TCB
satisfies at least its functional protection requirements.
For CS2, FT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
FT-1: Conformance Testing
The developer shall test the TCB interface to show
that all claimed protection functions work as
stated in the TCB interface description.
The developer shall correct all flaws discovered
by testing and shall retest the TCB until the
protection functions are shown to work as claimed.
4.6 User's Guidance
User's guidance is an operational support assurance
component that ensures that usage constraints assumed by the
protection profile are understood by the users of the product.
It is the primary means available for providing product users
with the necessary background and specific information on how
to correctly use the product's protection functionality.
For CS2, UG-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
UG-1: Users' Guide
The developer shall provide a Users' Guide which
describes all protection services provided and
enforced by the TCB. The User's Guide shall
describe the interaction between these services
and provide examples of their use. The User's
Guide may be in the form of a summary, chapter or
manual. The User's Guide shall specifically
describe user responsibilities. These shall
encompass any user responsibilities identified in
the protection profile.
4.7 Administrative Guidance
Administrative guidance is an operation support assurance
component that ensures that the environmental constraints
assumed by the protection profile are understood by
administrative users and operators of the IT product. It is
the primary means available to the developer for providing to
administrators and operators detailed, accurate information
on how to configure and install the product, operate the IT
product is a secure manner, make effective use of the
product's privileges and protection mechanisms to control
access to administrative functions and data bases, and to
avoid pitfalls and improper use of the administrative
functions that would compromise the TCB and user security.
For CS2, AG-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
AG-1: Basic Administrative Guidance
The developer shall provide a Trusted Facility
Manual intended for the product administrators
that describes how to use the TCB security
services (e.g., Access Control, System Entry, or
Audit) to enforce a system security policy. The
Trusted Facility Manual shall include the
procedures for securely configuring, starting,
maintaining, and halting the TCB. The Trusted
Facility Manual shall explain how to analyze audit
data generated by the TCB to identify and document
user and administrator violations of this policy.
The Trusted Facility Manual shall explain the
privileges and functions of administrators. The
Trusted Facility Manual shall describe the
administrative interaction between security
services.
The Trusted Facility Manual shall be distinct from
User Guidance, and encompass any administrative
responsibilities identified in security
management.
4.8 Flaw Remediation Procedures
Flaw remediation is an operational support assurance
component that ensures that flaws (i.e, deficiencies in a
product that enables a user external to the TCB to violate the
functional requirements of a protection profile) that are
discovered by the product consumers will be tracked,
corrected, and disseminated to the affected customers.
For CS2, FR-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
FR-1: Basic Flaw Remediation
Flaw Tracking Procedures: The developer shall
establish a procedure to track all reported
protection flaws in each release of the product.
The tracking system shall include a description of
the nature and effect of each flaw and the status
of finding a correction to the flaw.
Flaw Repair Procedures: The developer shall
establish a procedure to identify corrective
actions for protection flaws.
Customer Interaction Procedures: The developer
shall provide flaw information and corrections to
registered customers.
4.9 Trusted Generation
Trusted generation is an operational support assurance
component that ensures that the copy of the product's TCB that
is configured and activated by the consumer exhibits the same
protection properties as the master copy of the product's TCB
that was evaluated for compliance with the protection profile.
The trusted generation procedures must provide some
confidence that the consumer will be aware of what product
configuration parameters can affect the protection properties
of the TCB. The procedures must encourage the consumer to
choose parameter settings that are within the bounds assumed
during the product evaluation.
For CS2, TG-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
TG-2: Trusted Generation With Fail-Safe Defaults
The developer shall establish and document the
procedures that a customer must perform to
generate an operational TCB from the delivered
copy of the master TCB. The customer documentation
shall identify any system parameters, which are
initialized or set during system generation, that
affect the TCB's conformance to the protection
profile and state the acceptable ranges of values
for those parameters. The product shall be
delivered with each of these parameters set to its
fail-safe defaults.
4.10 Evidence of TCB Protection Properties
The documentation of the TCB protection properties includes
the definition of the functional component requirements,
their modeling (if any), and their interpretation within a
product's TCB. For each requirement of a protection profile,
a description, definition (an informal, descriptive
specification), or a formal specification of the TCB
components and their operation corresponding to the
requirement must be provided.
For CS2, EPP-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPP-1 Evidence of TCB Correspondence to the Functional
Requirements
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. The TCB properties, which
are defined by this correspondence, shall be
explained in this documentation.
4.11 Evidence of Product Development
Product development evidence consists of the TCB design
evidence including the documentation of the TCB interface, TCB
elements, TCB structure, TCB structuring support, and TCB
design disciplines. The TCB implementation evidence includes
TCB source code, and the processor hardware and firmware
specifications.
For CS2, EPD-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPD-2: Description Of The TCB External Interface
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. The developer shall also
provide an informal access control model and its
interpretation within the TCB. The TCB properties,
which are defined by this correspondence, shall be
explained in this documentation.
4.12 Evidence of Functional Testing
Functional testing evidence includes the testing itself,
the test plans, and test documentation results. Test plans
consist of: the description definition or specification of the
test conditions; the test data, which consists of the test
environment set-up; the test parameters and expected
outcomes; and a description of the test coverage.
For CS2, EFT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EFT-1: Evidence of Conformance Testing
The developer shall provide evidence of the
functional testing that includes the test plan,
the test procedures and the results of the
functional testing.
4.13 Evidence of Product Support
Product support evidence consists of the development
environment and operational support documentation and tools.
The development environment evidence includes the
documentation of the product life-cycle process,
configuration management procedures enforced, and the trusted
distribution mechanisms and procedures used. It also
includes: the identification of the tools used in the product
development, configuration management, and trusted
distribution; and the characteristics that make those tools
suitable for the development of product protection.
For CS2, EPS-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPS-1: Evidence of Basic Product Support
The developer shall provide evidence that
describes the policies, procedures, and plans
established by the developer to satisfy the
Operational Support and Development Environment
requirements of the protection profile.
4.14 Test Analysis
Test analysis determines whether the product meets the
functional protection requirements defined in the protection
profile. Functional testing is based on operational product,
the TCB's functional properties, the product's operational
support guidance, and other producer's documentation as
defined by the development evidence requirements. Functional
test analysis is based on the achieved test results as
compared to the expected results derived from the development
evidence.
For CS2, TA-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
TA-1: Elementary Test Analysis
The evaluator shall assess whether the producer
has performed the activities defined in the
development assurance requirements of the
protection profile for functional testing and
whether the producer has documented these
activities as defined in the development evidence
requirements of the protection profile. The
evaluator shall analyze the results of the
producer's testing activities for completeness of
coverage and consistency of results. The evaluator
shall determine whether the product's protection
properties, as described in the product
documentation have been tested. The evaluator
shall assess testing results to determine whether
the product's TCB works as claimed.
4.15 Independent Testing
Independent testing determines whether the product's TCB
meets the functional protection requirements as defined in the
functionality chapter of this Protection Profile. Testing is
based on the operational product, the TCB's functional
properties, the product's operational support guidance, and
other producer's documentation as defined by the Development
Evidence requirements.
For CS2, IT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
IT-1: Elementary Independent Testing
A tester, independent of the producer or
evaluator, shall perform functional and elementary
penetration testing. This testing shall be based
on the product's user and administrative
documentation, and on relevant known penetration
flaws. Satisfactory completion consists of
demonstrating that all user-visible security
enforcing functions and security-relevant
functions work as described in the product's user
and administrative documentation and that no
discrepancies exist between the documentation and
the product. Test results of the producer shall be
confirmed by the results of independent testing.
The evaluator may selectively reconfirm any test
result.
If the independent testing is performed at beta-
test sites, the producer shall supply the beta-
test plan and the test results. The evaluator
shall review the scope and depth of beta testing
with respect to the required protection
functionality, and shall verify independence of
both the test sites and the producer's and beta-
test user's test results. The evaluator shall
confirm that the test environment of the beta-test
site(s) adequately represents the environment
specified in the protection profile.
4.16 Operational Support Review
Operation support review establishes the level of review
required to determine whether the product meets the
requirements as defined in the protection profile's
Development Assurance subsections for Operational Support
including, at the CS2 level, the User and Administrative
Guidance documents.
For CS2, OSR-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
OSR-1 Elementary Operational Support Review
The evaluator shall review all documentation
focused on the activities of product use (e.g.,
Users Manuals) and product administration
including installation, operation, maintenance,
and trusted recovery (e.g., Trusted Facility
Management Manuals). This review shall assess the
clarity of presentation, difficulty in locating
topics of interest, ease of understanding, and
completeness of coverage. The need for separate
manuals dedicated to protection-relevant aspects
of the product should be assessed for
effectiveness.
COMMERCIAL SECURITY 3 (CS3)
CS3 compliant products provide enhanced protection
beyond those of the CS1 and CS2 Protection Profiles
by providing administrative and access control
features to centrally control access to information
and other resources based on roles. Through the use
of role based access controls, a variety of
organization specific non-discretionary integrity
and confidentiality policies can be specified and
enforced. In addition, CS3 provides stronger
authentication measures, more administrative tools,
and requires a greater degree of assurance
evidence.
CS3 Functional Component Summary
.------------------------------------------------------.
| | Component | |
| Component Name | Code | Level |
|======================================================|
| Security Policy Support: |
|----------------------------------+-----------+-------|
| Identification & Authentication | I&A | 4 |
|----------------------------------+-----------+-------|
| System Entry | SE | 3 |
|----------------------------------+-----------+-------|
| Trusted Path | TP | 1 |
|----------------------------------+-----------+-------|
| Audit | AD | 3 |
|----------------------------------+-----------+-------|
| Access Control | AC | 2+ |
|----------------------------------+-----------+-------|
| Availability: |
|----------------------------------+-----------+-------|
| Resource Allocation | AR | 1 |
|----------------------------------+-----------+-------|
| Security Management | SM | 3 |
|----------------------------------+-----------+-------|
| Reference Mediation | RM | 1 |
|----------------------------------+-----------+-------|
| TCB Protection | P | 1 |
|----------------------------------+-----------+-------|
| Physical Protection | PP | 1 |
|----------------------------------+-----------+-------|
| Self Checking | SC | 3 |
|----------------------------------+-----------+-------|
| TCB Initialization & Recovery | TR | 3 |
|----------------------------------+-----------+-------|
| Privileged Operations | PO | 2 |
|----------------------------------+-----------+-------|
| Ease-of-Use | EU | 3 |
`------------------------------------------------------'
CS3 Assurance Package Summary
.---------------------------------------.
| Assurance Components | T3+ |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-2 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-1 |
|--------------------------------+------|
| TCB Modular Decomposition | ---- |
|--------------------------------+------|
| TCB Structuring Support | SP-1 |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | ---- |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-1 |
|--------------------------------+------|
| Penetration Analysis | PA-1 |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-2+|
|--------------------------------+------|
| Flaw Remediation | FR-2 |
|--------------------------------+------|
| Trusted Generation | TG-2 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | LC-1 |
|--------------------------------+------|
| Configuration Management | CM-1 |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP2 |
|--------------------------------+------|
| Product Development | EPD1 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT1 |
|--------------------------------+------|
| Penetration Analysis | EPA1 |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Product Support | EPS1 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-2 |
|--------------------------------+------|
| Independent Testing | IT-1 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | DER1 |
|--------------------------------+------|
| Operational Support | OSR1 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | DA-1 |
|--------------------------------+------|
| Implementation | ---- |
`---------------------------------------'
CS3 Rationale
2.17 Introduction
As outlined in the Federal Criteria, this rationale
describes the protection philosophy, how the security
features are intended to be used, the assumptions about the
environment in which a compliant product is intended to
operate, the threats within that environment, and the security
features and assurances that counter these threats. At the CS3
level, the features used to counter threats and the strength
of the assurance evidence is enhanced over CS1 and CS2 and is
indicated in the text through bold italics.
2.17.1 Protection Philosophy
Any discussion of protection necessarily starts from a
protection philosophy, i.e., what it really means to call the
product "secure." In general, products will control access to
information and other resources through the use of specific
security features so that only properly authorized
individuals or processes acting on their behalf will be
granted access. For CS1, four fundamental requirements are
derived for this statement of protection:
o Access authorization
o Accountability
o Assurance
o Availability of Service
The totality of the functionality that enforces the access
authorization and accountability protection philosophy is
comprised of the hardware, software, and firmware of the
Trusted Computing Base (TCB). CS3 requires the TCB to be self-
protecting and resistant to bypass so that it is effective at
countering identified threats. CS3 also requires effective
management of security attributes and configuration
parameters. The assurance protection philosophy is comprised
of the development process, operational support, development
environment, development evidence, and evaluation process
assurances. Each of these are explained below.
2.17.1.1 Access Authorization
The access authorization portion of the philosophy of
protection for this profile addresses subject and object
access mediation. For CS3 compliant products, access
authorization has been further refined to include system
entry, subject and object mediation based on system entry,
subject and object mediation based on role identifiers, and
privileged operations.
2.17.1.1.1 System Entry
CS3 provides the capability for an system administrator to
establish, maintain, and protect information from
unauthorized access, and defines the identities of and
conditions under which users may gain entry into the system.
These system entry controls are based on user identification,
role membership, time, location, and method of entry. CS3
strengthens the requirement for locking interactive sessions
by requiring the display device to be cleared or overwritten
to make the current contents of the screen unreadable.
2.17.1.1.2 Subject and Object Access Mediation
CS1 and CS2 provide protected access to resources and
objects. CS3 compliant products also provide the capability
of specifying and enforcing access control decisions based on
roles [12][13]. In many organizations, the end users do not
"own" the information and the programs for which they are
allowed access. For these organizations, the corporation or
agency is the actual "owner" of the system objects as well as
the programs that process them. Control is often based on
employee functions rather than on ownership.
Access control decisions are often determined by the roles
individual users take on as part of an organization. The
definition of a role includes the specification of duties,
responsibilities, and qualifications. For example, the roles
an individual associated with a hospital can assume include
doctor, nurse, clinician, and pharmacist. Roles in a bank
include teller, loan officer, and accountant. Roles can also
apply to military systems; for example, target analyst,
situation analyst, and traffic analyst are common roles in
tactical systems. A Role Based Access Control (RBAC) policy
bases access control decisions on the functions a user is
allowed to perform within an organization. Under this policy,
the users cannot pass access permissions to other users at
their discretion.
For each role, a set of transactions associated with the
role is maintained. A transaction can be thought of as a
transformation procedure [12] (a program or a portion of a
program) plus a set of associated data items. In addition,
each role has an associated set of individual members.
The determination of membership and the allocation of
transactions to a role is in compliance with organization
specific non-discretionary policies. These policies can be
derived from existing laws, ethics, regulations, or generally
accepted practices. These policies are non-discretionary in
the sense that they are unavoidably imposed on all users.
For subject and object access mediation, CS3 also provides
for additional time and location access control attributes.
At a minimum, these attributes include the user's port of
entry.
2.17.1.1.3 Privileges
CS3 supports and promotes the separation and use of
privileges for TCB modules. A privilege enables a subject to
perform a security relevant operation that, by default, is
denied. Privileges cover all security aspects of a product,
including TCB operations performed by system administrators.
CS3 compliant products have tightly controlled privilege
definitions as well as control over subjects that hold
privileges.
2.17.1.2 Accountability
The accountability portion of the philosophy of protection
for this profile addresses user identification and
authentication (I&A), requirements for security auditing, and
a Trusted Path between a user and the operating system. Each
of these are explained below.
2.17.1.2.1 Identification and Authentication
User identification is required to support access control
and security auditing. This includes the capability to
establish, maintain, and protect a unique identifier for each
authorized user. User identification is functionally
dependent on authentication. Authentication is a method of
validating a person as a legitimate user.
User authentication in most computer systems has been
provided primarily through the use of passwords. CS2 supports
a variety of password features that give the product a great
amount of flexibility in the generation of passwords, in
password security, password features, and password
administration. For most products, a great deal of confidence
is placed on maintaining the privacy of passwords belonging
to individuals. I&A prevents unauthorized individuals from
logging into the product, therefore, password management is
essential to secure product operations. The risk of losing a
password is addressed within CS2 through promoting the use of
stringent password management practices.
In addition, CS2 allows for stronger authentication
approaches. CS2 specifies that a unique identifier be
associated with each trusted subject such as print spoolers,
database management system services, and transaction
processing monitors. It also requires the TCB to maintain,
protect, and display status information for all active users
and all enabled or disabled user identities or accounts.
CS3 also provides for stronger authentication mechanisms
for those commercial and government environments that need
such assurance, such as law enforcement agencies, nuclear
facilities, and commercial airports. These other approaches
can be categorized as "something a user is," which can be
indicated through the use of a unique characteristic that a
person possesses, or "something a user has," such as a smart
card. For example, biometrics is a "something you are"
approach for identifying individuals through the use of a
unique physical characteristic associated with a person such
as a fingerprint or a retina pattern. In many respects, the
biometrics approach to user identification is a cleaner and
more secure approach than a password mechanism. This method
eliminates the concern over the compromise of a password.
However, while biometric devices are currently available,
their expense makes them impractical for most applications.
"Something a user has" requires a physical device that users
must have in their possession at authentication time. Usually,
these devices require the user to enter a Personal
Identification Number (PIN) in case the device is lost or
stolen.
2.17.1.2.2 Audit
For most secure products, a capability must exist to audit
the security relevant events. As each user performs security
relevant tasks, the product must record the user identifier,
the action performed, and the result in a security log. For
CS31compliant products, a capability is specified to allow a
system administrator to access and evaluate audit
information. This capability provides a method of protection
in the sense that all security relevant events that occur
within a computer system can be logged and the responsible
user held accountable for his/her actions. Audit trails are
used to detect and deter penetration of a computer system and
to reveal activity that identifies misuse.
CS3 provides for an effective audit mechanism by supporting
the following basic security characteristics. It provides the
ability to:
o review the use of I&A mechanisms;
o discover the introduction of objects into a user's
address space;
o discover the deletion of objects;
o discover actions taken by computer operators and
system administrators;
o audit attempts to violate resource allocation limits;
o protect the audit data so that access to it is limited
to system administrators that are authorized to
examine audit information;
o discover the use of privileges, such as changing the
ownership of an object;
o have the audit mechanism act as a deterrent against
penetrators or hackers; and
o to use audit reduction tools for assessing the damage
that may result in the event of a violation of the
implemented security policy. These tools have the
capability of selectively reviewing the actions of one
or more users or roles, actions performed on a
specific object or system resource, and actions
associated with specific access control attributes.
2.17.1.3 Availability of Service
CS3 promotes the continuous accessibility and usability of
resources. The TCB provides the capability to detect and
recover from discontinuity of service using some combination
of automatic and procedural techniques. Also, resource
allocation requirements replace restrictions on the number of
subjects and objects a user may have allocated at any given
time. This prevents one individual user from denying access
to another user's subject and object space.
2.17.1.4 Assurance
Assurance addresses all areas of product development
assurance and evaluation assurance. The Development assurance
addresses the development process, operational support, the
development environment, and the development evidence.
Development process assurance defines the additional efforts
that a developer must undertake to satisfy the assurance
objectives while creating the product. It specifies how the
TCB should be designed and supported by the implementation as
well as how it should be tested. Operational support assurance
defines the documentation of the security features for both
administrative and non-administrative users as well as
requirements for TCB flaw remediation and TCB generation.
Development environment assurance includes requirements for
defining the product's life cycle and specific features for
configuration management. Development evidence assurance
defines the TCB's protection properties, details the
requirements for product testing and analysis, and defines the
requirements for product support. Evaluation assurance
establishes that the product, and the context in which it is
developed and supported, is commensurate with the development
assurance requirements.
The T3+ Assurance Package was chosen for CS3. This package
is indicated as being TS3+ since an additional component was
included for flaw remediation. This enhanced assurance level
is intended to include the best of the commercial computer
products designed to satisfy functional requirements. As
such, this package includes several extensions to the
assurance components of the previous two packages.
The intent of product development assurance for this
package is both to establish that the external behavior of the
product conforms to its user level and administrative
documentation and to provide visibility into the internal
structure of the product's TCB. For this reason, requirements
for Descriptive Interface Specifications (DIS) and modular
decomposition have been added. TCB element identification and
security functional testing have also been extended and
penetration testing requirements have been provided to
support the added assurances of external behavior.
The intent of the operational support assurance for this
package is to establish a level of user and administrative
guidance and product information that enables the correct
product installation and the use of product security features.
The developer is required to establish and document a policy
for responding to customer inquiries and flaw remediation.
Similarly, the development environment assurances are
intended to provide a level of control over the product
configuration and production, including well-defined coding
standards and strict configuration management processes. This
level of development environment assurance is similar to that
used in the most advanced commercial development
organizations.
The development evidence required for this package is
commensurate with the assurances required. The intent of this
package is to require the type of assurance evidence that is
generated during commercial development oriented towards of
high-quality products.
At the T3+ level, evaluation support assurance determines
whether the product meets the functional requirements for
testing analysis and for independent testing. Operational
support evaluation assurance determines whether the product
documentation correctly describes the security relevant
operations. Development environment assurance determines
whether the product meets the requirements as defined in the
Protection Profile's development assurance subsections.
Design assurance determines whether the product meets the
design requirements as defined in the Development Process
Assurance section of this Protection Profile.
Also for CS3, flaw remediation was included in this
package. Flaw remediation is important for commercial
environments since it ensures that flaws (i.e, deficiencies
in a product that enables a user external to the TCB to violate
the functional requirements of a protection profile) that are
discovered by the product consumers will be tracked,
corrected, and disseminated to the affected customers.
Vendors are required to separate protection-relevant fixes
from those that are not protection-relevant and must document
points of contact for customer error reports.
2.17.1.5 Intended Method of Use
All individual users (both administrative and non-
administrative users) are assigned a unique user identifier.
This user identifier supports individual accountability. The
operating system authenticates the claimed identity of the
user before allowing the user to perform any further actions.
Upon successful authentication, users are restricted to
accessing programs, transactions, and information in a manner
that is consistent with their assigned role(s).
Products that comply with the CS3 Protection Profile are
provided with the capability of assigning privileges to TCB
modules. These privileges are used to control access to user
and role registration files, password files, and audit trails.
Privileges are associated with functional components so that
only the privileges necessary to complete a security relevant
task can be assigned at a given time. Also, privileges are
associated with TCB operations performed by system
administrators. This capability is particularly important to
prevent a "privileged user" or "superuser" from having a wide
set of privileges when only a subset is needed.
In addition, CS3 provides administrative and access control
capabilities that allow for the central administration of a
non-discretionary access control policy based on roles. A role
specifies a user's set of transactions that allow the user to
access resources through specific functions. Transactions can
only be allocated to roles by system administrators.
Membership to a role can only be granted and revoked by system
administrators.
Products that comply with CS3 specifications are intended
to be used within the following operational constraints:
o The information system is designed to be administered
as a unique entity by a single organization.
o The information system is designed to manage
computing, storage, input/output, and to control the
sharing of resources among multiple users and computer
processes.
o The administrative and non-administrative users are
identified as distinct individuals.
o For role based access control, administrators are
responsible for interpreting and enforcing
organizational policies and protection guidelines
that are derived from existing laws, ethics,
regulations, or generally accepted practices.
o The information system provides facilities for real-
time interaction with users that have access to input/
output devices.
o System administrators are selectively assigned
privileges that are minimally necessary to perform
their security related task.
2.17.2 Environmental Assumptions
A product designed to meet the CS3 Protection Profile is
intended to be a general purpose, multi-user operating system
that runs on either a workstation, minicomputer, or mainframe.
CS3 compliant products are expected to be used for both
commercial and government environments. The information being
processed for both commercial and government environments may
be unclassified, sensitive-but-unclassified, or single-level
classified, but not multi-level classified information.
The following specific environmental conditions have been
assumed in specifying CS3:
o The product hardware base (e.g., CPU, printers,
terminals, etc.), firmware, and software will be
protected from unauthorized physical access.
o There will be one or more personnel assigned to manage
the product including the security of the information
it contains.
o The operational environment will be managed according
to the operational environment documentation that is
required in the assurance chapter of the Protection
Profile.
o Access control to information and other resources is
determined by the roles that individual users have.
o The IT product provides a cooperative environment for
users to accomplish some task or group of tasks.
o The processing resources of the IT product, including
all terminals, are assumed to be located within user
spaces that have physical access controls established.
o The IT product provides facilities for some or all of
the authorized users to create programs that use an
Application Programming Interface (API) to enable them
to protect themselves and their objects from
unauthorized use.
o Fail-safe defaults are included for the access control
attributes for the defined subjects and objects for
the product.
2.17.3 Expected Threats
In general, the choice of which Protection Profile to
choose depends upon the level of security that is required for
that particular organizational environment. The lowest level,
the CS1 level, is intended for those commercial and government
environments where all the system personnel are trusted and
all the data on the system is at the same classification
level. For example, a government agency where all personnel
has a government clearance, all data is unclassified, and
there is no outside network connections would be an ideal
candidate for CS1, i.e., the threats to be countered are such
that only a minimal level of trust is needed. However, most
commercial and government environments are more complex and
require a higher degree of trust. CS2 addresses the security
needs for the mainstream commercial and government
environments. It provides a higher level of trust for those
organizations that need to enforce a security policy where
there is no need for different classifications of data. CS3
is intended to provide the highest level of trust for
commercial and government environments. It is intended to be
used in those environments where a great deal of trust is
required, such as in law enforcement agencies, nuclear
facilities, or commercial airports. It provides the strongest
features, mechanisms, and assurances to counter these
threats.
A product that is designed to meet the CS3 Protection
Profile and operate within its assumed environment will
provide capabilities to counter these threats. It should be
noted, however, that although a product may faithfully
implement all the features and assurances specified in this
Protection Profile, the complete elimination of any one threat
should not be assumed. A product that is designed to meet the
CS3 Protection Profile is generally known to be more effective
at countering the threats than products that meet the CS1 and
CS2 Protection Profiles. CS3 products counter all the CS1 and
CS2 threats, and contain stronger features and more assurance
evidence than CS1 and CS2 products. In addition to countering
CS1 and CS2 threats, CS3 compliant products provide protection
capabilities to counter one additional threat as follows:
1. AN UNAUTHORIZED USER MAY ATTEMPT TO GAIN ACCESS TO THE
SYSTEM
For CS1 compliant products, the threat of an unauthorized
user gaining access to the system is primarily addressed by
I&A features that allow the TCB to verify the identity of
individuals attempting to gain access to the system. This is
accomplished through the use of passwords.
Although not a direct countermeasure, auditing requirements
are specified at the CS1 level to provide the capability to
perform an after-the-fact analysis of unauthorized system
entry and login attempts. This provides an opportunity for the
system administrators to take corrective actions, such as
strengthening existing user authentication methods or
requiring users to change their passwords.
For CS2 compliant systems, the threat of an unauthorized
user gaining access to the system is primarily addressed by
stronger I&A features and system entry requirements.
CS2 specifies password requirements that promote a strong
organizational password management program. These
requirements specify that: null passwords cannot be used
during normal operations; passwords be stored in a one-way
encrypted form; the clear text representation of a password
be automatically suppressed; passwords have a minimum-length;
and that the system utilize a password complexity-checking
algorithm. An advisory capability is also provided to exclude
a list of customer-specified passwords. Such requirements
support the use of passwords that are effective against
password guessing. To further reduce the probability of a
password being guessed, requirements limit the number of
attempted login attempts that can be made by a user associated
with a specific user identifier. The probability of a single
password being guessed is further reduced by requirements for
password aging, by having limitations on password reuse, and
by allowing users to choose a password that is already
associated with another user identifier.
CS2 also allows for a password generating capability.
Because random passwords can be difficult to remember and
users are tempted to write them down, requirements are
specified for the generation of passwords that are easy to
remember (i.e., pronounceable). Additionally, an advisory
requirement is specified to allow users to choose from a list
of alternative passwords.
To minimize the threat that a password has been
compromised, a requirement exists to allow a user to change
the password. Because a password can be compromised by
observing the characters on a terminal screen as it is being
typed, there is a requirement to blot out the clear-text
representation of the password on the display device.
In addition, requirements are specified to display an
advisory warning message to all users prior to system logon
to discourage a would-be system penetrator from attempting an
unauthorized system entry. Such a message can also provide a
basis for subsequent prosecution. System entry requirements
also specify additional controls on identified and
authenticated users entering the system. Once a user is
authenticated, a check is made to determine if the user is
allowed further entry. System entry is granted only in
accordance with the authenticated user's access control
attributes. These conditions are in terms of a user's identity
and his/her membership in roles. In addition, CS2 specifies
system entry requirements to display to an authorized user,
upon successful system entry, the date and time, method of
access or port of entry, and the number of failed logon
attempts since the last successful system entry by that user
identifier. These requirements provide a user with the
capability to detect attempted or successful system
penetrations. In addition, requirements are specified to lock
and terminate an interactive session after an administrator-
specified period of user inactivity, and also for the TCB to
appear to perform the entire user authentication procedure
even if the user identification entered is invalid. The TCB
also provides a protected mechanism to allow or deny system
entry based on specified ranges of time. Also, conditions for
system entry via dial-up lines are required to be specified.
I&A requirements are also enhanced over those of CS1 by
specifying requirements for the identification for each
trusted user, and by specifying requirements for system
administrators to disable a user's identity or account when
the number of unsuccessful logon attempts exceeds an
administrator specified threshold. This is intended to
mitigate the effectiveness of successive attacks of system
penetration.
Although passwords are currently the most common method for
authenticating users, CS3 supports the inclusion of a variety
of additional authentication mechanisms, such as smart-cards,
cryptographic-based authentication, and biometrics. Also,
access control attributes have been enhanced to include time
and location capabilities. This allows an organization to
acquire and integrate stronger user authentication
capabilities when penetration threats warrant such
capabilities.
Also, during system entry, users are granted entry based
on their role. In addition, CS3 extends the system entry
requirements of CS2 by specifying features for user-initiated
locking of the user's interactive sessions (e.g., keyboard
locking).
2. AN AUTHORIZED USER MAY ATTEMPT TO GAIN ACCESS TO
RESOURCES WHEN THE USER IS NOT ALLOWED ACCESS
An authorized user can gain access to unauthorized
resources by assuming the user identifier of another user and
thus gaining their associated access rights. This is addressed
through the use of passwords.
Once an authorized user has gained access to the system,
the threat still remains for a user to gain access to
resources when the uer is not authorized. At the resource
level, CS2 specifies access control features to mediate (i.e.,
distribute, review, and revoke) user access to a subset of
resources.
The object reuse feature has been specified to ensure that
resource contents are cleared before they are reused. This
reduces the vulnerability that the resource contents can be
read before it is overwritten.
To address the vulnerability associated with passwords, CS2
specifies password requirements that promote a strong
organizational password management program. Besides those
password requirements that address penetration threats from
unauthorized users, other password requirements have been
specified to counter the threat of an insider (authorized
user) attack. There are password requirements that specify
that passwords must always be stored in encrypted format and
that passwords can never be included in audit trail data.
Also, in the event that a user selects a password that is
already in use by another user, requirements disallow the
system from acknowledging the dual association.
In addition, CS3 specifies access control features to limit
the roles that may change to another role that provides any
additional privileges to that user. These controls are based
on the role identifier. Also, administrators are provided with
capabilities through the use of protected mechanisms to set
and control security related parameters, defaults,
thresholds, attributes, and other security related data. This
provides the ability to effectively specify and control access
to resources based on site specific protection policies.
CS3 also specifies that privileges must be associated with
TCB modules, TCB calls, and accesses to privileged TCB objects
(e.g., user and role registration files. password files, audit
log files), and with TCB operations performed by
administrative users.
CS2 specifies requirements for a direct communication
channel, i.e., a trusted path, between the user and the
operating system to counter spoofing threats. This security
feature provides confidence that a user at a terminal will
communicate directly with the TCB rather than to malicious
code. In particular, to counter the threat of an authorized
user creating a spoof of legitimate user identifier
authorization prompts, CS2 specifies requirements for a
direct communication path between the user and the
authentication system.
Requirements are also specified to display an advisory
warning message to all users prior to system logon to
discourage unauthorized system entry. Such a message can also
provide a basis for subsequent prosecution.
Once an authorized user has been identified and
authenticated, system entry control can help counter threats
of inadvertent, deliberate, and coerced entry performed in an
unauthorized manner by an authorized user. At the end of
system entry control, the user bears the access-control
attributes determined during the I&A process, provided that
the system entry conditions are satisfied. These conditions
can be specified in terms of a user's identity, role identity,
or mode of access.
CS2 also provides other security features. Application
programming interfaces are provided so that applications can
protect themselves and their objects from unauthorized use.
CS2 specifies lists of user identities authorized to enter the
system via dial-up lines. CS2 also specifies general
authentication facilities for use by application developers,
system administrators, and users for the protection of
resources.
To guard against unauthorized user access, CS3 specifies
that TCB privileges can be associated with TCB operations
performed by system administrators.
Roles are also used as an access control attribute in that
access to a particular object may be granted or denied based
on a specific role. CS3 also specifies general authentication
facilities for use by application developers, system
administrators, and users for the enhanced protection of
resources. CS3 specifies requirements to provide users with
the ability to clear the content of their screens and lock
their interactive session without having to logoff the system.
This reduces the likelihood that a user will leave his or her
terminal while engaged in an active session. Also at the CS3
level, privileges are associated with TCB operations
performed by system administrators. To further strengthen TCB
mediation, CS3 expands the scope of authorization rules to
include all subject and object contents and all access control
attributes.
3. AN AUTHORIZED USER MAY ATTEMPT TO GAIN ACCESS TO A ROLE
WHEN THE USER IS NOT ALLOWED ACCESS
This threat is countered by having a protected mechanism in
the TCB that allows only authorized users to access a
particular role. Users are prompted for the role they wish to
assume for that login session during system entry, and entry
will be denied if the user tries to assume a role for which
he/she is not authorized. This is assured through security
functional testing and through penetration testing. Also,
only system administrators are allowed to set role
characteristics and to include or delete users from a
particular role. Attempts to access and use a particular role
can be audited, and the use and definition of roles are
explained in security documentation.
4. SECURITY RELEVANT ACTIONS MAY NOT BE TRACEABLE TO THE
USER ASSOCIATED WITH THE EVENT
CS3 accountability and audit requirements are specified to
provide the capability to track security relevant actions
performed by users and link such actions, if possible, to the
responsible identifier. Audit mechanisms are responsible for
the monitoring and detecting of real or potential security
violations or events. These audit events can include
successful or unsuccessful: I&A events, the introduction of
objects into a user's address space, the deletion of objects,
and actions taken by computer operators and system
administrators. Each audit record includes the date, time,
location, type of event, identity of the user and object
involved, and the success or failure of the event.
Requirements are specified to protect audit trail data and
the audit control mechanism from unauthorized access,
modification, or destruction. Audit features are specified to
provide post-collection audit analysis on specific data
items, users, and privileged operations. Also, a capability
is provided for trusted application programs to append data
to the security audit trail.
System entry control helps to enhance accountability by
providing a time, space, and mode-of-entry context to each
action for which the user is held accountable. These added
constraints help to give additional assurance that the proper
user is held responsible for a set of authorized actions.
At the CS2 level, tools are specified to enhance the
effectiveness of user accountability. CS3 specifies
requirements to provide tools to verify the consistency of the
audit trial data and the selection of audit events. Tools are
also specified for post-collection analysis to selectively
review various actions.
Authentication capabilities are extended to provide for
additional authentication methods, for example, tokens or
biometrics.
5. THE PRODUCT MAY BE DELIVERED, INSTALLED, AND THEN USED
IN AN UNSECURED MANNER
This threat is countered by explicitly requiring that the
product be delivered with all security features turned on.
This ensures that the product is secure by default rather than
insecure by default. This is complemented by allowing many
security features to be configurable so that, as a specific
organization gains experience with the actual threats in its
environment, the organization can adjust the degree of
security in their system. There are several requirements that
reinforce the "security by default" perspective during
initial installation. Requirements for security
administrative documentation are specified to increase the
likelihood that the administrator will install and start the
system in a secure manner.
6. SECURITY BREACHES MAY OCCUR BECAUSE AVAILABLE SECURITY
FEATURES ARE NOT USED OR ARE USED IMPROPERLY
Requirements for authentication, system and access control,
security management, and product documentation provide a
basis for countering this threat. Authentication requirements
provide for password management procedures to reduce the
possibility of easy to guess passwords and to initialize
passwords for users. Password generation algorithms are
provided that generate easy to remember passwords and that
give the user a choice of passwords. In addition, CS3 provides
for a capability to import and export objects and subjects
with defined access control attributes. This ensures that
access control attributes are maintained with the subject or
object during import and export operations.
Security management requirements are specified for listing,
setting, and updating all of the system security parameters
and attributes. These parameters and attributes pertain to
identification, authentication, system entry, access control,
audit trail analysis and availability features for the system
and for individual users. This allows a system administrator
to confirm that the system is properly configured and, if
necessary, to modify the existing configuration and
attributes. In addition, security management requirements
provide for routine control and maintenance of system
resources.
Product documentation requirements for users,
administrators, and operators describe how to perform
security relevant functions in a secure manner.
CS3 also extends security management requirements with
respect to policy-oriented security issues. This includes a
means to initialize administrative privileges and
administrative identification, authentication, and system
entry attributes. Because CS3 compliant systems support
multiple I&A methods, the administrator is provided with a
capability to specify an authentication method on a per access
control attribute basis.
CS3 further extends security management requirements by
specifying tools for system administration. These tools
include tools for verifying consistency and proper system
installation, and for verifying that the TCB does not contain
extraneous programs or data.
7. SECURITY BREACHES MAY OCCUR BECAUSE OF TCB PENETRATION
TCB protection is a fundamental capability of CS compliant
products. The security components and mechanisms described in
this Protection Profile depend upon the integrity of the TCB
and on the TCB being isolated and non-circumventable. CS1
specifies requirements for a common and basic set of security
features to protect the TCB from outside penetration.
This threat is also countered through product assurance.
The TCB interface definition establishes the boundary between
the TCB and its internal users. Security functional testing
establishes that these TCB definitions and properties satisfy
the requirements of this Protection Profile and provides
evidence against TCB penetration.
This threat is also countered through penetration testing.
The penetration analysis evidence includes, in addition to
penetration test plans and results configured in the same
manner as the security functional testing evidence, the
documentation of the penetration-resistance testing methods
and tools, conditions that were verified, the outcomes of the
verification and, when appropriate, the scenario of the
discovered penetration flaws. Also, the developer must show
that all discovered flaws have been eliminated and that no new
flaws have been introduced. The cause of every discovered
penetration flaw, or class of penetration flaws, must also be
documented. At the CS3 level of trust, the system developer
also must illustrate how, in addition to system reference
manuals and TCB interface descriptions, the DIS, source code,
and hardware and firmware specifications are used to define
penetration test conditions. Also, for each test, the system
developer must document all test conditions, data, and
coverage.
8. USERS MAY BE ABLE TO BYPASS THE SECURITY FEATURES OF THE
SYSTEM
This threat is countered by authentication, access control,
audit, TCB isolation, TCB non-circumventability, and
reference mediation requirements. Authentication requirements
protect authentication data from unauthorized users. Resource
access control requirements protect access control data.
Audit requirements provide for the logging of successful
and unsuccessful accesses to resources as well as for changes
made to the system security configuration and system software
in the event that the system security features have been
bypassed.
CS1 specifications for reference mediation protects the
integrity of the access control mechanism and the TCB's
functionality. Starting at CS1, requirements exist for TCB
mediation of user references to objects and to security
relevant services.
CS1-compliant products maintain a domain for its own
execution to protect it from external interference and
tampering. Such requirements address TCB isolation and non-
circumventability of TCB isolation functions.
This threat is also countered through product assurance.
The definition of TCB properties assures the consistency of
the TCB's behavior. The identification of TCB elements
provides the set of elements that determine the protection
characteristics of a product. The TCB interface definition
establishes the boundary between the TCB and its internal
users. Security functional testing establishes that these TCB
definitions and properties satisfy the requirements of the
Protection Profile, and provide evidence against subjects
being able to bypass the security features of the system. At
the CS2 level, procedures also have to be established for
developers to accept customer reports of protection problems
and requests for corrections to those problems. Also, when the
product is delivered, all security related parameters must be
set to its fail-safe defaults.
9. SUBJECTS MAY BE DENIED CONTINUED ACCESSIBILITY TO THE
RESOURCES OF THE SYSTEM (I.E., DENIAL OF SERVICE)
Reliability of service requirements promote the continued
accessibility of system resources by authorized subjects.
These requirements principally counter threats related to
intentional or unintentional denial of service attacks. The
requirements include detecting and reporting facilities,
features to monitor and control the consumption of disk space
and CPU usage, controls to limit systematically the disabling
of user identifiers, mechanisms for recovery in the event of
a system crash, resource quotas, destruction of errant
processes and facilities for software, and data backup and
restoration. In particular, mechanisms are specified for
recovery and system start-up, and for a maintenance mode of
operation.
CS3 compliant systems provide the capability to detect and
recover from discontinuity of service using some combination
of automatic and procedural techniques. This capability is
intended to counter the threat that subjects may be denied
continued accessibility to the resources of the system (i.e.,
denial of service). Also, users are notified in advance to
change their password, so that access to the system is not
denied without warning. An advisory capability exists to allow
a system administrator to use null passwords during system
start-up. This allows a system administrator to access the
system even if the password mechanism has been compromised.
In addition, audit trails are compressed to avoid excessive
consumption of disk space.
CS3 provides the capability to place restrictions on the
number of subjects and objects a user may have allocated at
any given time. Such capabilities provide protection against
a single user denying access to another user's subject and
object space. Resource quota requirements are extended to
require auditing when attempts are made to violate resource
allocation limits.
At the CS3 level, an optional capability can be provided to
detect and report conditions that degrade service below a
system-specifiable minimum. Also, CS3 provides enhanced TCB
checking capabilities by extending TCB checks to not only
hardware and firmware but also to software elements (i.e.,
code and data structures).
10. THE INTEGRITY OF THE SYSTEM MAY BE COMPROMISED
At the CS3 level, requirements are specified for TCB
recovery and start-up to promote the secure state of the
system in the event of a system failure or discontinuity of
service. These features are intended to minimize the
likelihood of the loss of user objects during system recovery.
To protect audit trail data, a mechanism is specified to
automatically copy the audit trail file to an alternative
storage area. Also, mechanisms that guarantee the consistency
of the audit trail data after system failures and
discontinuity of operation is provided.
CS2 compliant products provide the capability to validate
the correct operation of the TCB software, firmware, and
hardware. Such features are important to ensure that the
software, hardware, and firmware are in working order.
Requirements for the physical security of the TCB and of
functions and devices that establish physical control over the
TCB are identified and provided. In addition, power-on tests,
loadable tests and operator-controlled tests are specified to
validate the correct operation of the TCB hardware and
firmware.
CS3 also extends the TCB initialization and recovery
capabilities by specifying requirements for automatic
procedures to protect the secure state of the system in the
event of a system failure or discontinuity of service. Also,
automated procedures are provided to assure that after system
failure or discontinuity of operations a secure state is
obtained without undue loss of system or user objects.
CS3 extends the TCB initialization and recovery
capabilities by specifying automated procedures to assure
that after system failure, other discontinuity, or start-up,
a secure state is obtained without undue loss of system or
user objects.
At the CS3 level, tools are specified to verify the
consistency of audit data and also to check for storage medium
and file system integrity. An optional capability is provided
to allow for the encryption of data to preserve the integrity
of data in an object.
In addition, fail-safe defaults are specified for the
access control attributes of subjects, objects, and services
used in common system configurations.
CS3 Functionality
3. Introduction
This section provides detailed functionality requirements
that must be satisfied by an Commercial Security 3 (CS3)
compliant product. Note that all plain text are words taken
directly from CS2 `s functionality chapter for the components
or, for those components not included in CS2, directly from
the Federal Criteria. Any assignments or refinements that were
made at CS2 are indicated by italics. Any assignments or
refinements made to the text in CS2 or the Federal Criteria
are indicated by bold italics. A Protection Profile
requirement is an assignment when it is directly taken as
stated from the component without change or when a binding is
made to a Federal Criteria threshold definition. A Protection
Profile requirement is a refinement when the requirement is
taken to a lower level of abstraction.The characterization of
Protection Profile requirements as being either assignments
or refinements can be found at each component level. Also,
note that, unlike the Federal Criteria, there are some items
that are considered to be "advisory," i.e.,an item marked
advisory is a desirable feature but is not required for that
component. Each advisory item is marked with an "(A)".
This Protection Profile for CS3 utilizes the following
levels from the Federal Criteria. Note that not all the
components from the Federal Criteria are reflected in this
Protection Profile; there are no specific requirements for
those components that are not listed. Also note that a "+"
after the component level number indicates that a requirement
was included from a higher level of that component.
CS3 Functional Component Summary
.------------------------------------------------------.
| | Component | |
| Component Name | Code | Level |
|======================================================|
| Security Policy Support: |
|----------------------------------+-----------+-------|
| Identification & Authentication | I&A | 4 |
|----------------------------------+-----------+-------|
| System Entry | SE | 3 |
|----------------------------------+-----------+-------|
| Trusted Path | TP | 1 |
|----------------------------------+-----------+-------|
| Audit | AD | 3 |
|----------------------------------+-----------+-------|
| Access Control | AC | 2+ |
|----------------------------------+-----------+-------|
| Availability: |
|----------------------------------+-----------+-------|
| Resource Allocation | AR | 1 |
|----------------------------------+-----------+-------|
| Security Management | SM | 3 |
|----------------------------------+-----------+-------|
| Reference Mediation | RM | 1 |
|----------------------------------+-----------+-------|
| TCB Protection | P | 1 |
|----------------------------------+-----------+-------|
| Physical Protection | PP | 1 |
|----------------------------------+-----------+-------|
| Self Checking | SC | 3 |
|----------------------------------+-----------+-------|
| TCB Initialization & Recovery | TR | 3 |
|----------------------------------+-----------+-------|
| Privileged Operations | PO | 2 |
|----------------------------------+-----------+-------|
| Ease-of-Use | EU | 3 |
`------------------------------------------------------'
3.1 Identification & Authentication
All users of the product must be identified and
authenticated. A login process is established that interacts
with the user in order to provide the information necessary
for identification and authentication. The identification and
authentication process begins the user's interaction with the
target product. First, the user supplies a unique user
identifier to the TCB. Then, the user is asked to authenticate
that claimed identity by the TCB. The user identifier is used
for accountability. Therefore, the proper maintenance and
control of the identification mechanism and the
identification databases are vital to TCB security. Once a
user has supplied an identifier to the TCB, the TCB must
verify that the user really corresponds to the claimed
identifier. This is done by the authentication mechanism as
described by the following requirements.
For the CS3 level, I&A-4 was assigned from the Federal
Criteria. Refinements were made from CS2 and the Federal
Criteria to limit the enforcement of separate user
authentication procedures to system administrators.
I&A-4 Exception-Controlled Identification and
Authentication
1. The TCB shall require users to identify
themselves to it before beginning to perform any
other actions that the TCB is expected to mediate.
The TCB shall be able to enforce individual
accountability by providing the capability to
uniquely identify each individual user. The TCB
shall also provide the capability of associating
this identity with all auditable actions taken by
that individual. Furthermore, the TCB shall have
the capability of associating a unique identity
with each privileged subject, i.e. transaction
processing monitors.
2. The TCB shall maintain authentication data that
includes information for verifying the identity of
individual users (e.g., passwords), as well as
information for determining the product policy
attributes of individual users, i.e. roles. These
data shall be used by the TCB to authenticate the
user's identity and to ensure that the attributes
of subjects external to the TCB that may be
created to act on behalf of the individual user
satisfy the product policy. The control of user
identification data shall be limited to system
administrators, except that a user shall be
allowed to modify his/her own authentication data
within prescribed limits (e.g., changing his/her
own password).
The TCB shall be able to incorporate and use
installable authentication mechanisms, such as
token-based cards, biometrics, or trusted third-
party mechanisms, in the place of or in addition
to the default authentication (e.g., password-
based) mechanism, to authenticate the user. The
TCB shall be able to enforce separate user
authentication procedures based on specific policy
attributes. The enforcement of separate user
authentication procedures shall be limited to
system administrators.
3. The TCB shall protect authentication data so
that it cannot be used by any unauthorized user.
The TCB shall appear to perform the entire user
authentication procedure even if the user
identification entered is invalid. Error feedback
shall contain no information regarding which part
of the authentication information is incorrect.
The TCB shall end the attempted login session if
the user performs the authentication procedure
incorrectly for a number of successive times
(i.e., a threshold) specified by an authorized
system administrator. The default threshold shall
be three times. When the threshold is exceeded,
the TCB shall send an alarm message to the system
console and/or to the administrator's terminal,
log this event in the audit trail, and delay the
next login by an interval of time specified by the
authorized system administrator. The default time
interval shall be 60 seconds. The TCB shall
provide a protected mechanism to disable the user
identity or account when the threshold of
successive, unsuccessful login attempts is
violated more than a number of times specified by
the administrator. By default, this mechanism
shall be disabled (as it may cause unauthorized
denial of service).
4. The TCB shall have the capability to maintain,
protect, and display status information for all
active users (e.g., users currently logged on,
current policy attributes) and of all user
accounts (i.e., enabled or disabled user identity
or account).
5. Whenever passwords are used as a protection
mechanism, then, at a minimum:
a. The TCB shall not indicate to the user if he/she
has chosen a password already associated with
another user.
b. The TCB shall store passwords in a one-way
encrypted form.
(1) The TCB shall require privilege to access
encrypted passwords.
c. The TCB shall automatically suppress or fully
blot out the clear-text representation of the
password on the data entry/display device.
d. The TCB shall, by default, prohibit the use of
null passwords during normal operation.
(1) A capability, accessible only to an system
administrator, to allow null passwords during
non-normal operations, such as system start-
up, manual recovery, or maintenance mode, on a
per-user identifier or per-port basis may be
provided. (A)
e. The TCB shall provide a protected mechanism to
allow a user to change his or her password. This
mechanism shall require re-authentication of the
user identity.
(1) The TCB shall provide a protected mechanism to
set or initialize passwords for users. The use
of this mechanism shall be limited to system
administrators.
f. The TCB shall enforce password aging on a per-
user identifier or per-group basis (i.e., a user
shall be required to change his or her password
after a system-specifiable minimum time). The
default for all non-system administrators shall
be sixty days.
(1) The default for system administrator
identifiers shall be thirty days.
(2) After the password aging threshold has been
reached, the password shall no longer be
valid, except as provided in 5 g below.
The control of password aging shall be limited to
system administrators.
g. The TCB shall provide a protected mechanism to
notify users in advance of requiring them to
change their passwords. This can be done by
either:
(1) Notifying users a system-specifiable period
of time prior to their password expiring. The
default shall be seven days.
- or -
(2) Upon password expiration, notifying the user
but allowing a system-specifiable subsequent
number of additional logons prior to requiring
a new password. The default shall be two
additional logons.
The control of user password expiration defaults
shall be limited to system administrators.
h. Passwords shall not be reusable by the same user
identifier for a system-specifiable period of
time. The default shall be six months. The
control of password re-use shall be limited to
system administrators.
i. The TCB shall provide an algorithm for ensuring
the complexity of user-entered passwords that
meets the following requirements:
(1) Passwords shall meet a system-specifiable
minimum length requirement. The default
minimum length shall be eight characters.
(2) The password complexity-checking algorithm
shall be modifiable by the TCB. The default
algorithm shall require passwords to include
at least one alphabetic character, one numeric
character, and one special character.
(3) The TCB should provide a protected mechanism
that allows systems to specify a list of
excluded passwords (e.g., company acronyms,
common surnames). (A)
(a) The TCB should prevent users from selecting
a password that matches any of those on the
list of excluded passwords. (A)
The control of password complexity shall be limited
to system administrators.
j. If password generation algorithms are present,
they shall meet the following requirements:
(1) The password generation algorithm shall
generate passwords that are easy to remember
(i.e., pronounceable).
(2) The TCB should give the user a choice of
alternative passwords from which to choose.
(A)
(3) Passwords shall be reasonably resistant to
brute-force password guessing attacks.
(4) If the "alphabet" used by the password
generation algorithm consists of syllables
rather than characters, the security of the
password shall not depend on the secrecy of the
alphabet.
(5) The generated sequence of passwords shall have
the property of randomness (i.e., consecutive
instances shall be uncorrelated and the
sequences shall not display periodicity).
3.2 System Entry
Once a user is authenticated, a check is made to see if the
user is allowed to access the product. The qualifying checks
for system entry can include time-of-day, day-of-week, date,
location of terminal, or means of access (e.g., dial-up port),
and membership in roles.
For the CS3 level, SE-3 was assigned from the Federal
Criteria. An assignment was made from CS2 or the Federal
Criteria for specifying a role as a user policy attribute.
SE-3 Session Locking and Unlocking
1. Prior to initiating the system login procedure,
the TCB shall display an advisory warning message
to the user regarding unauthorized use of the
system and the possible consequences of failure to
heed this warning.
a. The message shall be system-specifiable.
b. The TCB shall be able to display a message of up
to twenty lines in length.
c. The following message shall be displayed by
default:
"NOTICE: This is a private computer system.
All users of this system are subject to
having their activities audited. Anyone
using this system consents to such
auditing. All unauthorized entries or
activities revealed by this auditing can be
used as evidence and may lead to criminal
prosecution."
The control of system entry messages shall be
limited to system administrators.
2. Before system entry is granted to a user, the
identity of that user shall be authenticated by
the TCB. If the TCB is designed to support
multiple login sessions per user identity, the TCB
shall provide a protected mechanism to enable
limiting the number of login sessions per user
identity or account with a default of a single
login session. The control of this mechanism to
limit the number of login sessions shall be
limited to system administrators.
3. The TCB shall grant system entry only in
accordance with the authenticated user's policy
attributes. The system entry conditions shall be
expressed in terms of users' policy attributes,
i.e., user identity and membership to roles. If no
explicit system-entry conditions are defined, the
system-entry default shall be used (e.g., the
correct user authentication). The TCB shall
provide a protected mechanism to allow or deny
system entry based on specified ranges of time.
Entry conditions using these ranges shall be
specified using time-of-day, day-of-week, and
calendar dates. The control of system entry
conditions shall be limited to system
administrators.
The TCB shall provide a protected mechanism to
allow or deny system entry based on location or
port of entry. Conditions for system entry via
dial-up lines (e.g., lists of user identities
authorized to enter the system via dial-up lines),
if any, shall be specified.The control of these
mechanisms shall be limited to system
administrators.
4. The TCB shall provide a protected mechanism that
enables authorized administrators to display and
modify the policy attributes used in system-entry
control for each user. The conditions under which
an unprivileged user may display these attributes
shall be specified.
5. Upon a user's successful entry to the system,
the TCB shall display the following data to the
user and shall not remove them without user
intervention: (1) the date, time, means of access
and port of entry of the last successful entry to
the system; and (2) the number of successive,
unsuccessful attempts to access the system since
the last successful entry by the identified user.
6. The TCB shall either lock or terminate an
interactive session after an administrator-
specified interval of user inactivity. The default
value for the lock interval shall be five minutes.
The default value for session termination shall be
fifteen minutes. The TCB shall also provide a
mechanism for user-initiated locking of the user's
own interactive sessions (e.g., keyboard locking)
that includes: (1) clearing or over-writing
display devices to make the current contents
unreadable; (2) requiring user authentication
prior to unlocking the session; and (3) disabling
any activity of the user's data entry/display
devices other than unlocking the session.
3.3 Trusted Path
A Trusted Path ensures that users have direct, unencumbered
communication with the TCB. A Trusted Path may be required at
various times during a subject session and also may be
initiated by a user during a TCB interaction.
For the CS3 level, TP-1 was assigned from the Federal
Criteria. There are no refinements from CS2 or the Federal
Criteria.
TP-1 Login Trusted Path
The TCB shall support a trusted communication path
between itself and the user for initial
identification and authentication. Communications
via this path shall be initiated exclusively by a
user.
a. The TCB shall provide a protected mechanism by
which a display device may force a direct
connection between the port to which it is
connected and the authentication mechanism.
3.4 Audit
Audit supports accountability by providing a trail of user
actions. Actions are associated with individual users for
security-relevant events and are stored in an audit trail.
This audit trail can be examined to determine what happened
and what user was responsible for a security relevant event.
The audit trail data must be protected from unauthorized
access, modification, or destruction. In addition, the audit
trail data must be available in a useful and timely manner for
analysis.
Audit data is recorded from several sources (such as the
TCB or privileged applications) to produce a complete picture
of a user's security relevant actions. Therefore, audit data
must be correlated across audit collection systems. The
mechanisms providing audit data recording must be tailorable
to each product's needs. Both the audit data itself and the
mechanisms to determine what audit data is recorded are
protected by privileges. Once the audit data is recorded, it
is analyzed and reported. Reporting can be by reports
generated on request.
For the CS3 level, AD-3 was assigned from the Federal
Criteria. A refinement was made to audit attempts to
circumvent or gain unauthorized access to resource allocation
limits.
AD-3 Audit Tools
1. The TCB shall be able to create, maintain, and
protect from modification or unauthorized access
or destruction an audit trail of accesses to the
objects it protects. The audit data shall be
protected by the TCB so that read access to it is
limited to those who are authorized for audit
data.
The TCB shall support an application program
interface that allows a privileged application to
append data to the security audit trail or to an
applications-specified alternative security audit
trail.
The TCB should support an option to maintain the
security audit trail data in encrypted format. (A)
2. The TCB shall be able to record the following
types of events:
- use of the identification and authentication
mechanisms, and system entry events;
- access control events selectable on a per
user, per subject, per object, per role, and/or
per policy attribute basis; i.e., introduction of
objects into a user's address space (e.g., file
open, program initiation), creation and deletion
of subjects and objects; distribution and
revocation of access rights; changes of subject
and object policy attributes; acquisition and
deletion of system privileges.
-actions taken by computer operators and system
administrators and/or system security officers;
i.e., privileged operations such as the
modification of TCB elements; accesses to TCB
objects (at a minimum, access to an object shall
include disk file access, tape volume, or tape
file access); changes of policy attributes of
users, TCB configuration and security
characteristics, and system privileges; selection
and modification of audited events.
- attempts to circumvent or otherwise gain
unauthorized access to resource allocation limits.
The events that are auditable by default, and
those that are required for successful auditing of
other events, which may not be disabled, shall be
defined. The TCB shall provide a protected
mechanism that displays the currently selected
events and their defaults. The use of this
mechanism shall be restricted to authorized system
administrators.
3. For each recorded event, the audit record shall
identify: date and time of the event, user, type
of event, and success or failure of the event. For
identification/authentication events the origin of
request (e.g., terminal ID) shall be included in
the audit record. For events that introduce an
object into a user's address space and for object
deletion events the audit record shall include the
name and policy attributes of the object.
The character strings input as a response to a
password prompt shall not be recorded in the
security audit trail.
4. The TCB shall provide a protected mechanism to
turn auditing on and off, and to select and change
the events to be audited and their defaults,
during the system operation. The use of this
mechanism shall be restricted to authorized system
administrators. The system administrator shall be
able to selectively audit the actions of one or
more users based on individual identity and/or
object policy attributes. Audit review tools shall
be available to authorized system administrators
to assist in the inspection and review of audit
data, and shall be protected from unauthorized
use, modification, or destruction.
The TCB shall provide tools for audit data
processing. These shall include specifically
designed tools: for verifying the consistency of
the audit data; for verifying the selection of
audit events; for audit trail management. The
audit trail management tools shall enable:
- creation, destruction, and emptying of audit
trails; use of warning points regarding the size
of the audit data, and modification of the audit
trail size;
-formatting and compressing of event records;
-displaying of formatted audit trail data; and
-maintaining the consistency of the audit trail
data after system failures and discontinuity of
operation.
The TCB shall provide a protected mechanism for
the automatic copying of security audit trail
files to an alternative storage area after a
system-specifiable period of time.
The TCB shall provide a protected mechanism for
the automatic deletion of security audit trail
files after a system-specifiable period of time.
The default shall be thirty days.
(a) It shall not be possible to delete the
security audit trail before it gets copied
to an alternate storage area.
(b) It shall be possible to disable this mechanism.
The use of audit trail management functions shall
be limited to system administrators.
5. Audit review tools shall be available to
authorized users to assist in the inspection and
review of audit data, and shall be protected from
unauthorized modification or destruction. The TCB
shall also provide tools for post-collection audit
analysis (e.g., intrusion detection) that shall be
able to selectively review (1) the actions of one
or more users (e.g., identification,
authentication, system-entry, and access control
actions); (2) the actions performed on a specific
object or system resource; and (3) all, or a
specified set of, audited exceptions; and (4)
actions associated with a specific
policyattributes.The review tools shall be able to
operate concurrently with the system operation.
3.5 Access Control
Once the user has been granted access, the question of which
objects the authenticated user may access still remains. An
owner, or an authorized user, allows or denies to other users
access to that object. The requirements below describe subject
accesses to objects.
For the CS3 level, AC-2+ was assigned from the Federal
Criteria.his level is indicated as being AC-2+ because
requirements were included from level AC-4 (to include the
requirements for time and location dependency conditions).
These are indicated in the text by an "[AC-4]" in front of the
requirement. This component level was refined from CS2 and the
Federal Criteria by specifying access control decisions based
on roles.
AC-2+ Basic Access Control
1. Definition of Access Control Attributes
The TCB shall define and protect access control
attributes for subjects and objects. Subject
attributes shall include named individuals or
defined roles or both. Object attributes shall
include defined access rights (i.e., read, write,
execute) that can be assigned to subject
attributes.
The TCB shall be able to assign access rights to
role identities.
If multiple access control policies are supported,
the access control attributes corresponding to
each individual policy shall be identified.
[AC-4]: The subject and object attributes shall
accurately reflect the sensitivity and/or
integrity of the subject or object.The subject's
access control attributes also shall include time
and location attributes that can be assigned to
authenticated user identities.
2. Administration of Access Control Attributes
The TCB shall define and enforce rules for
assignment and modification of access control
attributes for subjects and objects.
The TCB shall provide a protected mechanism for
roles as follows:
a. A user identifier shall be able to be associated
with one or more roles.
b. The TCB shall provide a protected mechanism to
list the names of all roles.
c. The TCB shall provide a protected mechanism to
list the membership of any role.
Rules for maintaining role membership shall be
provided. These rules shall include those for
displaying and modifying the list of users
belonging to a role and the role attributes of those
users.
The effect of these rules shall be that access
permission to an object by users not already
possessing access permission is assigned only by
authorized users.
Only the current owner or system administrators
shall modify access control attributes on objects.
The TCB shall provide a protected mechanism to
modify role membership. The use of this mechanism
shall be under the control of system
administrators. Authority to modify specific role
membership may be delegated.
The TCB shall provide a protected mechanism by which
the user identifier associated with a subject
attribute can be changed while the subject is
active. It shall also provide a protected mechanism
for limiting the user identifiers that may change
to a user identifier that would provide any
additional access rights. The control of these
mechanisms shall be limited to system
administrators.
[AC-4]: These rules shall allow authorized users
to specify and control sharing of objects by named
individuals or defined roles of individuals, or by
both, and shall provide controls to limit
propagation of access rights, (i.e., these rules
shall define the distribution, revocation, and
review of access control attributes). The controls
defined by these rules shall be capable of
specifying for each named object, a list of
individuals and a list of roles of named
individuals, with their respective access rights
to that object. Furthermore, for each named
object, it shall be possible to specify a list of
named individuals and a list of roles of named
individuals for which no access to the object is
given. These controls shall be capable of
including or excluding access to the granularity
of a single user.These controls shall also be
capable of specifying access-time dependency
(i.e., the effect of the distribution and
revocation of access control attributes take place
at a certain time and shall last for a specified
period of time), and/or access-location dependency
(i.e., shall specify the locations from which the
distribution and revocation of access rights shall
take place).
The rules for assignment and modification of
access control attributes shall include those for
attribute assignment to objects during import and
export operations. If different rules of
assignment and modification of access control
attributes apply to different subjects and/or
objects, the totality of these rules shall be
shown to support the defined policy.
3. Authorization of Subject References to Objects
[AC-4]: The TCB shall define and enforce
authorization rules for the mediation of subject
references to objects. These rules shall be based
on the access control attributes of subjects and
objects. These rules shall, either by explicit
user action or by default, provide that objects
are protected from unauthorized access. These
rules shall include time-of-access and location-
of-access controls defined for subjects and
objects.
For each object, the authorization rules of the TCB
shall be based on a protected mechanism to specify
roles with their specific access rights to that
object.
The authorization rules shall be defined in terms
of subject authorization conditions for accessing
the object (i.e., on <subject, action, object>
tuples.
At a minimum, the authorization rules shall be
defined as follows:
a. The access rights associated with a user
identifier shall take precedence over the access
rights associated with any roles of which that
user identifier is a member.
b. When a user identifier can be an active member of
multiple roles simultaneously, or if the access
rights associated with the user identifier
conflict with the access rights associated with
any role in which the user is a member, it shall
be possible for an system administrator to
configure rules that combine the access rights to
make a final access control decision.
c. The TCB shall provide a protected mechanism to
specify default access rights for user
identifiers not otherwise specified either
explicitly by a user identifier or implicitly by
role membership.
The scope of the authorization rules shall include
a defined subset of the product's subjects and
objects and associated access control attributes.
The coverage of authorization rules shall specify
the types of objects and subjects to which these
rules apply. If different rules apply to different
subjects and objects, the totality of these rules
shall be shown to support the defined policy.
If multiple policies are supported, the
authorization rules for each policy shall be
defined separately. The TCB shall define and
enforce the composition of policies, including the
enforcement of the authorization rules (e.g.,
subject and object type coverage, enforcement
precedence).
4. Subject and Object Creation and Destruction
The TCB shall control the creation and destruction
of subjects and objects. These controls shall
include object reuse. That is, all authorizations
to the information contained within a storage
object shall be revoked prior to initial
assignment, allocation or reallocation to a
subject from the TCB's pool of unused storage
objects; information, including encrypted
representations of information, produced by a
prior subjects' actions shall be unavailable to
any subject that obtains access to an object that
has been released back to the system.
3.6 Security Management
The management of security attributes and configuration
parameters is an important aspect of a secure product.
Mechanisms have to be provided to easily maintain the product,
and they must be protected so that only system administrators
can manage the security aspects of the product.
For the CS3 level, SM-2 was assigned from the Federal
Criteria. An assignment was made to this component from the
Federal Criteria to limit the number of login sessions and for
controlling the availability of system resources. A
refinement was made to provide system administrators with a
protected mechanism for grating and revoking role membership.
SM-3 Policy-Oriented Security Management
1. The TCB shall provide an installation mechanism
for the setting and updating of its configuration
parameters, and for the initialization of its
protection-relevant data structures before any
user or administrator policy attributes are
defined. It shall allow the configuration of TCB
internal databases and tables.
The TCB shall distinguish between normal mode of
operation and maintenance mode, and shall provide
a maintenance-mode mechanism for recovery and
system start-up.This mechanism shall include a
means to initialize administrative privileges and
administrative identification, authentication, and
system-entry attributes.
2. The TCB shall provide protected mechanisms for
displaying and modifying the security policy
parameters. These parameters shall include
identification, authentication, system entry and
access control parameters for the entire system
and for individual users.
The TCB shall have a capability to define the
identification and authentication policy on a
system-wide basis (e.g., password minimum and
maximum lifetime, password length and complexity
parameters). The TCB mechanisms shall have the
capability to limit: (1) maximum period of
interactive session inactivity, (2) maximum login
or session time, and (3) successive unsuccessful
attempts to log in to the system. In particular,
the TCB shall provide a protected mechanism to
specify that sessions be terminated rather than
locked after a period of inactivity. The control
of these mechanisms shall be limited to system
administrators.The TCB shall provide an
administrative capability to specify the
authentication method on a per policy-attribute
basis whenever multiple identification and
authentication methods are used; e.g., via user
passwords, tokens, or biometrics.
If the TCB is designed to support multiple login
sessions per user identity, the administrators
shall be able to limit the number of simultaneous
login sessions on an authorization-attribute basis.
The system-supplied default shall limit each user
identifier to one simultaneous logon session.
The TCB shall also have a capability to limit
the successive unsuccessful attempts to login from
a specific port of entry, and/or with a specific
user identity or account.
The TCB shall provide a mechanism to control the
availability of system resources via resource
quotas and quantity-of-resources limits.
3. The TCB shall provide protected mechanisms for
manually displaying, modifying, or deleting user
registration and account parameters. These
parameters shall include unique user identifiers,
their account, and their associated user name and
affiliation. The TCB shall allow the automatic
disabling of user identities and/ or accounts,
after a period during which the identity and/or
account have not been used. The time period shall
be administrator specified, with a specified
default provided. The TCB shall allow the
automatic re-enabling of disabled user identities
and/or accounts after an administrator-specified
period of time.
The TCB shall provide a means to uniquely identify
security policy attributes. It shall also provide
a means of listing all these attributes for a
user, and all the users associated with an
attribute. It shall be capable of defining and
maintaining the security policy attributes for
subjects including: defining and maintaining
privileges for privileged subjects, discretionary
and non-discretionary attributes, i.e., definition
and maintenance of roles, and centralized
distribution, review and revocation of policy
attributes.
System administrators shall be provided with a
protected mechanism for the purposes of granting
and revoking user membership to specific roles.
Administrative users shall also be provided with
tools for the creation of roles and for the
definition of role attributes.
4. The TCB shall support separate operator and
administrator functions. The operator functions
shall be restricted to those necessary for
performing routine operations. The operator
functions allow the enabling and disabling of
peripheral devices, mounting of removable storage
media, backing-up and recovering user objects;
maintaining the TCB hardware and software elements
(e.g., on site testing); and starting and shutting
down the system.
5. The use of the protected mechanisms for system
administration shall be limited to authorized
administrative users. The control of access-
control attributes shall be limited to the object
owner and to system administrators.
3.7 Reference Mediation
Reference mediation, that is, the control by the TCB of
subject accesses to objects, must be ensured so that the users
can have faith in the TCB's access control decisions. Also,
users must be ensured that all access to security services are
mediated by the TCB.
For the CS3 level, RM-1 was assigned from the Federal
Criteria. No refinements were made from CS2 or the Federal
Criteria.
RM-1 Mediation of References to a Defined Subject/Object
Subset
1. The TCB shall mediate all references to
subjects, objects, resources, and services (e.g.,
TCB functions) described in the TCB
specifications. The mediation shall ensure that
all references are directed to the appropriate
security-policy functions.
2. Reference mediation shall include references to
the defined subset of subjects, objects, and
resources protected under the TCB security policy,
and to their policy attributes, i.e., role
identifiers.
3. References issued by privileged subjects shall
be mediated in accordance with the policy
attributes defined for those subjects.
3.8 Resource-Allocation Requirements
This component restricts the allocation of subjects and
objects so that no one user through the exhaustion of resource
can deny service to other users. It further enables the TCB
to prioritize subject access to resources so that the highest
priority subject is given preferential treatment in its access
to objects.
For CS3l, AR-1 was assigned from the Federal Criteria. This
component was refined from the Federal Criteria by limiting
the control of the capability to place restrictions on the
number of subjects and objects to system administrators.
LEVEL - AR-1 Resource Restrictions
The TCB shall provide the capability to place
restrictions on the number of subjects and objects a user
may have allocated at any given time. The control of this
capability shall be limited to system administrators.
The TCB shall control a defined set of system resources
(e.g., memory, disk space) such that no one individual
user can deny access to another user's subject and object
space. All subjects, objects, and resources shall be
defined with default space or time quota and number-of-
resources attributes.
3.9 TCB Protection
TCB protection is a fundamental requirement for a secure
product. All of the security components and mechanisms that
have been described depend upon the integrity of the TCB and
on the TCB being isolated and non-circumventable. The TCB must
be resistant to outside penetration.
For the CS3 level, P-1 was assigned from the Federal
Criteria. No refinements were made from CS2 or the Federal
Criteria.
P-1 Basic TCB Isolation
The TCB shall maintain a domain for its own
execution that protects it from external
interference and tampering (e.g., by reading or
modification of its code and data structures). The
protection of the TCB shall provide TCB isolation
and noncircumventability of TCB isolation
functions as follows:
1. TCB Isolation requires that (1) the address
spaces of the TCB and those of unprivileged
subjects are separated such that users, or
unprivileged subjects operating on their behalf,
cannot read or modify TCB data structures or code,
(2) the transfers between TCB and non-TCB domains
are controlled such that arbitrary entry to or
return from the TCB are not possible; and (3) the
user or application parameters passed to the TCB
by addresses are validated with respect to the TCB
address space, and those passed by value are
validated with respect to the values expected by
the TCB.
2. Noncircumventability of TCB isolation
functions requires that the permission to objects
(and/or to non-TCB data) passed as parameters to
the TCB are validated with respect to the
permissions required by the TCB, and references to
TCB objects implementing TCB isolation functions
are mediated by the TCB.
3.10 Physical TCB Protection
Whenever the physical security of a product cannot be
established, then all of the software controls that have been
put into place are of no consequence. Therefore, physical TCB
protection is just as important as software protection.
Physical protection is based on a product's ability to
prevent, deter, detect, and counter physical attacks against
the product. Devices used to counter physical attacks must be
shown to be tamper-resistant and non-circumventable.
For the CS3 level, PP-1 was assigned from the Federal
Criteria. No further refinements were made from the Federal
Criteria.
PP-1 Administrative and Environment Protection
1. Administrative procedures and environmental
features necessary for establishing the physical
security of a product's TCB shall be defined.
2. Product functions and devices necessary to
establish physical control over the product's TCB
shall be identified and provided.
3.11 TCB Self-Checking
Validating the correct operation of the TCB firmware and
hardware is an important aspect of guaranteeing the integrity
of the product. Hardware and software features that validate
the correct operation of the product will be delivered with
the product to ensure that the hardware and firmware are
installed properly and are in working order.
For the CS3 level, SC-2 was assigned from the Federal
Criteria. The refinements from CS2 and the Federal Criteria
include providing for an encryption mechanism to preserve the
integrity of object data and providing for a tool to check for
storage medium and file system integrity, and for having
system operators perform operator-controlled tests. An
assignment was made to the configurable software features to
monitor system services and the corruption of access control
information.
SC-3 Software-Test Support
Hardware and/or software features shall be
provided that can be used to periodically validate
the correct operation of the on-site hardware and
firmware elements of the TCB. These features shall
include: power-on tests, loadable tests, and
operator-controlled tests.
The power-on tests shall test all basic components
of the TCB hardware and firmware elements
including memory boards and memory
interconnections; data paths; busses; control
logic and processor registers; disk adapters;
communication ports; system consoles, and the
keyboard speaker. These tests shall cover all
components that are necessary to run the loadable
tests and the operator-controlled tests.
The loadable tests shall cover: processor
components (e.g., arithmetic and logic unit,
floating point unit, instruction decode buffers,
interrupt controllers, register transfer bus,
address translation buffer, cache, and processor-
to-memory bus controller); backplane busses;
memory controllers; writable control memory for
operator-controlled and remote system-integrity
testing.
Operator-controlled tests shall be able to
initiate a series of one-time or repeated tests,
to log the results of these tests and, if any fault
is detected, to direct the integrity-test programs
to identify and isolate the failure.The execution
of operator-controlled tests shall be limited to
system operators.
Configurable software or firmware features shall
be provided that can be used to validate the
correct operation of the on-site software elements
(i.e., code and data structures) of the TCB. These
features may include, but are not limited to,
checksums and consistency checks for TCB elements
stored on storage media (e.g., disk-block
consistency invariants).
a. At a minimum, these features shall also address:
(1) Monitoring of system services
(2) Corruption of access control information.
The TCB should provide an encryption mechanism that
can be used to preserve the integrity of data in an
object. (A)
The TCB shall provide tools for checking storage
medium and file system integrity.
a. The TCB shall execute these tools periodically.
3.12 TCB Initialization and Recovery
The recovery and start-up of the TCB must be ensured so that
the product always remains in a secure state, whether the
recovery is performed manually or automatically.
For the CS3 level, TR-2 was assigned from the Federal
Criteria. An assignment was made at this component level to
specify that audit control data shall survive system restarts.
TR-3 Automated Recovery or Start-up
1. Procedures and/or mechanisms shall be provided
to assure that, after a TCB failure or other
discontinuity, recovery without protection
compromise is obtained. At a minimum, audit
control data (e.g., audit event masks) shall
survive system restarts.
2. Automated procedures, under the control of the
TCB, shall be provided to assure that after a
system failure, other discontinuity, or start-up,
a secure state is obtained without undue loss of
system or user objects. The security policy
properties, or requirements, used to determine
that a secure state is obtained shall be defined.
3.13 Privileged Operation
Privileges are associated with functional components so
that at any given time only those operations that are
associated with the privilege can be performed. The privileges
that a product needs must be identified and must cover all the
security aspects of the product, including the secure
administration of the product, and should be defined so that
there is not a single privileged mode for all of the TCB's
operations.
For the CS3 level, PO-2 was assigned from the Federal
Criteria. A refinement was made from CS2 and the Federal
Criteria by specifying that privileges be associated with
administrative roles and for controlling access to role
registration files.
PO-2 Privilege Association with TCB Modules
1. TCB privileges needed by individual functions,
or groups of functions, of a functional component
shall be identified. Privileged TCB calls or
access to privileged TCB objects, such as user and
group and role registration files, password files,
security and integrity-level definition file, role
definition file, audit-log file shall also be
identified. It shall be possible to associate TCB
privileges with TCB operations performed by
administrative users (i.e., administrative roles).
2.The modules of a TCB function shall be
associated only with the privileges necessary to
complete their task.
3. Support for product privilege implementation
and association with TCB modules provided by
lower-level mechanisms or procedures (e.g.,
operating system, processors, language) shall be
provided.
3.14 Ease-of-TCB-Use
If security mechanisms are not easy to use and maintain,
then administrative and non-system administrators may be
tempted to disable the security mechanisms. Therefore, ease
of use becomes an important element in the administration of
a secure product and in the creation of privileged
applications. It also minimizes errors on the part of both the
administrative and non-system administrators, and can serve
to minimize the consequences of these errors.
For the CS3 level, EU-3 was assigned from the Federal
Criteria. No refinements were made from CS2 or the Federal
Criteria.
EU-3 Common Configuration Coverage
1. The TCB shall provide well-defined actions to
undertake administrative functions. Fail-safe
default options shall be provided for security
parameters of administrative functions.
The TCB shall include fail-safe defaults for the
policy attributes of subjects, objects (e.g.,
devices) and services used in common system
configurations, as well as user-setable defaults
for these subjects and objects.
2. The TCB shall provide well-defined application
programming interfaces and programming functions
(e.g., libraries) for all its policies to support
the development of applications that can define
and enforce security policies on application-
controlled subjects and objects. The TCB shall
enable user-controlled reduction of permissions
available to applications.
CS3 Assurance
4. Introduction
This chapter provides the CS3 development and evaluation
assurance requirements package using the development and
evaluation assurance components defined in Volume I and the
package contained in Volume I, Appendix G of the Federal
Criteria. The structure of each assurance package follows that
of the assurance components (i.e., each package consists of
development process, operational support, development
environment, development evidence, and evaluation process
components).
Assurance Package T3+
The enhanced assurance level is intended to include the
best of the commercial computer products designed to satisfy
functional requirements. As such this package includes
several extensions to the assurance components of the previous
two packages.
The intent of product development assurance for this
package is both to establish that the external behavior of the
product conforms to its user level and administrative
documentation and to provide visibility into the internal
structure of the product TCB. For this reason, requirements
for Descriptive Interface Specifications (DIS) and modular
decomposition have been added. The TCB element identification
and functional testing, have also been extended and
penetration testing requirements added to support the added
assurances of external behavior.
The intent of the operational support assurance for this
package is to establish a level of user and administrative
guidance and product information that enables the correct
product installation and use of product security features. The
developer is required to establish and document a policy for
responding to customer inquiries and flaw remediation.
Similarly, the development environment assurances are
intended to provide the a level of control over the product
configuration and production, including well-defined coding
standards and strict configuration management processes. This
level of development environment assurance is similar to that
used in the most advanced commercial development
organizations.
The development evidence required for this package is
commensurate with the assurances required. The intent of this
package is to require the type of assurance evidence that is
generated during commercial development oriented towards of
high-quality products.
The intent of evaluation support assurance is to establish
that the product, and the context in which it is developed and
supported, is commensurate with the development assurance
requirements. At the T3+ level, testing analysis and the
requirement for independent testing determines whether the
product meets the functional protection requirements.
Operational support evaluation assurance determines whether
the product documentation correctly describes the security
relevant operations. Development environment assurance
determines whether the product meets the requirements as
defined in the protection profile's development assurance
subsections. Design assurance determines whether the product
meets the design requirements as defined in the Development
Process Assurance section of this Protection Profile.
Also for CS3, flaw remediation was included in this
package. Flaw remediation is important for commercial
environments since it ensures that flaws (i.e, deficiencies
in a product that enables a user external to the TCB to violate
the functional requirements of a protection profile) that are
discovered by the product consumers will be tracked,
corrected, and disseminated to the affected customers.
The following table summarizes the assurance components
that comprise T3+. Note that this package is indicated as
being T3+ since an additional component was included for flaw
remediation. Also note that the requirement for role based
administrative guidance was included from level AG-3 and is
indicated in the table below as "AG-2+" and in the component
text by the insertion of "[AG-3]"at the beginning of the
paragraph.
CS3 Assurance Package Summary
.---------------------------------------.
| Assurance Components | T3+ |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-2 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-1 |
|--------------------------------+------|
| TCB Modular Decomposition | ---- |
|--------------------------------+------|
| TCB Structuring Support | SP-1 |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | ---- |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-1 |
|--------------------------------+------|
| Penetration Analysis | PA-1 |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-2+|
|--------------------------------+------|
| Flaw Remediation | FR-2 |
|--------------------------------+------|
| Trusted Generation | TG-2 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | LC-1 |
|--------------------------------+------|
| Configuration Management | CM-1 |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP2 |
|--------------------------------+------|
| Product Development | EPD1 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT1 |
|--------------------------------+------|
| Penetration Analysis | EPA1 |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Product Support | EPS1 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-2 |
|--------------------------------+------|
| Independent Testing | IT-1 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | DER1 |
|--------------------------------+------|
| Operational Support | OSR1 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | DA-1 |
|--------------------------------+------|
| Implementation | ---- |
`---------------------------------------'
4.1 TCB Property Definition
The definition of TCB properties assures the consistency of
the TCB's behavior. It determines a baseline set of properties
that can be used by system developers and evaluators to assure
that the TCB satisfies the defined functional requirements.
For CS3, PD-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
PD-2 Informal Property Definition
The developer shall provide informal models for
the functional components and sub-components of
the profile. At a minimum, an informal model of
the access control components shall be provided.
Each informal model shall include (abstract) data
structures and operations defining each functional
component or sub-component, and a description of
the model properties. The developer shall
interpret (e.g., trace) the informal models within
the product TCB. For each model entity, the
developer shall: (1) identify the TCB elements and
their TCB interfaces (if any) that implement that
entity; (2) define the operation of these TCB
elements, and (3) explain why the operation of
these elements is consistent with the model
properties. The developer's interpretation of each
informal model, which defines the TCB properties,
shall identify all TCB elements that do not
correspond to any model entity and shall explain
why these elements do not render the TCB
properties invalid.
For the components that are not informally
modeled, the developer shall interpret the
functional requirements of the protection profile
within the product TCB. For each functional
requirement, the developer shall: (1) identify the
TCB elements and their TCB interfaces (if any)
that implement that requirement; (2) describe the
operation of these TCB elements, and (3) explain
why the operation of these elements is consistent
with the functional requirement. The developer's
interpretation of each functional requirement,
which describes the TCB properties, shall identify
all TCB elements that do not correspond to any
functional requirement and shall explain why these
elements do not render the TCB properties invalid.
4.2 TCB Element Identification
The identification of TCB elements (hardware, firmware,
software, code, and data structures) provides the set of
elements that determine the protection characteristics of a
product. All assurance methods rely on the correct
identification of TCB elements either directly or indirectly.
For CS3, ID-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
ID-2: TCB Element Justification
The developer shall identify the TCB elements
(i.e., software, hardware/firmware code and data
structures). Each element must be unambiguously
identified by its name, type, release, and version
number (if any).
The developer shall justify the protection
relevance of the identified elements (i.e., only
elements that can affect the correct operation of
the protection functions shall be included in the
TCB). If protection-irrelevant elements are
included in the TCB, the developer shall provide a
rationale for such inclusion.
4.3 TCB Interface Definition
The TCB interface establishes the boundary between the TCB
and its external users and application programs. It consists
of several components, such as command interfaces (i.e., user
oriented devices such as the keyboard and mouse), application
program interfaces (system calls), and machine/processor
interfaces (processor instructions).
For CS3, IF-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
IF-1: Interface Description
The developer shall describe all external (e.g.,
command, software, and I/O) administrative (i.e.,
privileged) and non-administrative interfaces to
the TCB. The description shall include those
components of the TCB that are implemented as
hardware and/or firmware if their properties are
visible at the TCB interface.
The developer shall identify all call conventions
(e.g., parameter order, call sequence
requirements) and exceptions signaled at the TCB
interface.
TCB Structuring Support
Structuring the TCB into modules is necessary. However, the
modular decomposition does not necessarily reflect the run-
time enforcement of the TCB structuring since the separation
of modules may not necessarily be supported by run-time
mechanisms. The run-time enforcement of internal TCB
structuring adds a measure of assurance that the TCB elements
that are critical to the enforcement of the protection
functions are separate from the non-critical elements. Also,
the use of run-time enforcement of TCB structuring helps
separate protection-critical TCB elements from each other,
thereby helping to enforce the separation of protection
concerns and minimizing the common mechanisms shared between
protection critical elements.
For CS3, SP-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
SP-1: Process Isolation
The TCB shall maintain process isolation.
4.4 Developer Functional Testing
Functional testing establishes that the TCB interface
exhibits the properties necessary to satisfy the requirements
of the protection profile. It provides assurance that the TCB
satisfies at least its functional protection requirements.
For CS3, FT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
FT-1: Conformance Testing
The developer shall test the TCB interface to show
that all claimed protection functions work as
stated in the TCB interface description.
The developer shall correct all flaws discovered
by testing and shall retest the TCB until the
protection functions are shown to work as claimed.
4.5 Penetration Analysis
Penetration analysis is an important assurance component
since the effectiveness of all security policies rely on the
penetration resistance of the TCB. TCB penetration analysis
consists of the identification and confirmation of flaws in
the design and implementation of protection functions that can
be exploited by unprivileged users or untrusted application
programs.
For CS3, PA-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
PA-1 Basic Penetration Testing
The developer shall define the TCB configuration,
interface, and protection functions that are
subject to penetration testing. For each test, the
developer shall identify the goal of the test and
the criteria for successful penetration. The
developer shall identify all product documentation
(e.g., system reference manuals) used to define
penetration-test conditions, and shall document
all test conditions, data (e.g., test set-up,
function call parameters, and test outcomes), and
coverage.
The penetration testing shall include, at a
minimum, known classes of penetration flaws found
in other TCBs (e.g., generic penetration flaws).
For each uncovered flaw, the developer shall
define and document scenarios of flaw
exploitation, and shall identify all penetration
outcomes resulting from that scenario.
4.6 User's Guidance
User's guidance is an operational support assurance
component that ensures that usage constraints assumed by the
protection profile are understood by the users of the product.
It is the primary means available for providing product users
with the necessary background and specific information on how
to correctly use the product's protection functionality.
For CS3, UG-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
UG-1: Users' Guide
The developer shall provide a Users' Guide which
describes all protection services provided and
enforced by the TCB. The User's Guide shall
describe the interaction between these services
and provide examples of their use. The User's
Guide may be in the form of a summary, chapter or
manual. The User's Guide shall specifically
describe user responsibilities. These shall
encompass any user responsibilities identified in
the protection profile.
4.7 Administrative Guidance
Administrative guidance is an operation support assurance
component that ensures that the environmental constraints
assumed by the protection profile are understood by
administrative users and operators of the IT product. It is
the primary means available to the developer for providing to
administrators and operators detailed, accurate information
on how to configure and install the product, operate the IT
product is a secure manner, make effective use of the
product's privileges and protection mechanisms to control
access to administrative functions and data bases, and to
avoid pitfalls and improper use of the administrative
functions that would compromise the TCB and user security.
For CS3, AG-2+ was assigned from the Federal Criteria. This
level is indicated as being "AG-2+" because requirements were
included from AG-3 for role based administrative guidance.
This is indicated in the text by an "[AG-3]" in front of the
paragraph and through the use of bold italics.
AG-2+: Detailed Administrative Guidance
[AG-3]: The developer shall provide a Trusted
Facility Manual intended for the product
administrators and operators that describes how to
use the TCB security services (e.g., Access
Control, System Entry, or Audit) to enforce a
system security policy. The Trusted Facility
Manual shall include the procedures for securely
configuring, starting, maintaining, and halting
the TCB. The Trusted Facility Manual shall explain
how to analyze audit data generated by the TCB to
identify and document user and administrator
violations of this policy. The Trusted Facility
Manual shall explain the unique security-relevant
privileges and functions of administrators and
operators. The Trusted Facility Manual shall also
explain the distinct security-relevant privileges
and functions of the TCB and how they can be
selectively granted to provide fine-grained,
multi-role system and application administration
policies. The Trusted Facility Manual shall
describe the administrative interaction between
security services.
The Trusted Facility Manual shall identify all
hardware, firmware, software, and data structures
comprising the TCB. The detailed audit record
structure for each type of audit event shall be
described. If covert channel handling is required,
the Trusted Facility Manual shall explain how
configure the product to mitigate, eliminate, or
audit covert channel exploitation.The Trusted
Facility Manual shall describe the cautions about
and procedures for using the TCB as a base for
site-specific secure applications. The Trusted
Facility Manual shall describe procedures for
securely regenerating the TCB after any part is
changed (e.g., due to adding devices or installing
flaw corrections to the TCB software).
The Trusted Facility Manual shall be distinct from
User Guidance, and encompass any administrative
responsibilities identified in security
management.
4.8 Flaw Remediation Procedures
Flaw remediation is an operational support assurance
component that ensures that flaws (i.e, deficiencies in the
product that enable a user external to the TCB to violate the
functional requirements of a protection profile) that are
discovered by the product consumers will be tracked and
corrected while the product is supported by the developer.
For CS3, FR-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
FR-2: Flaw Reporting Procedures
Flaw Tracking Procedures: The developer shall
establish a procedure to track all reported
protection flaws with each release of the product.
The tracking system shall include a description of
the nature and effect of each flaw and the status
of finding a correction to the flaw.
Flaw Repair Procedures: The developer shall
establish a procedure to identify corrective
actions for protection flaws. This procedure shall
include a policy to separate protection-relevant
from non-protection relevant corrections, changes,
or upgrades to the product.
Consumer Interaction Procedures: The developer
shall establish a procedure for accepting consumer
reports of protection problems and requests for
corrections to those problems. The developer shall
designate one or more specific points of contact
for consumer reports and inquiries about
protection issues involving the product. This
procedure and the designated points of contact
shall be provided in the consumer documentation
(e.g., the TFM or the SFUG).
4.9 Trusted Generation
Trusted generation is an operational support assurance
component that ensures that the copy of the product's TCB that
is configured and activated by the consumer exhibits the same
protection properties as the master copy of the product's TCB
that was evaluated for compliance with the protection profile.
The trusted generation procedures must provide some
confidence that the consumer will be aware of what product
configuration parameters can affect the protection properties
of the TCB. The procedures must encourage the consumer to
choose parameter settings that are within the bounds assumed
during the product evaluation.
For CS3, TG-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
TG-2: Trusted Generation With Fail-Safe Defaults
The developer shall establish and document the
procedures that a customer must perform to
generate an operational TCB from the delivered
copy of the master TCB. The customer documentation
shall identify any system parameters, which are
initialized or set during system generation, that
affect the TCB's conformance to the protection
profile and state the acceptable ranges of values
for those parameters. The product shall be
delivered with each of these parameters set to its
fail-safe defaults.
4.10 Life Cycle Definition
Life cycle definition is an assurance component for
establishing that the business practices used by a developer
to produce the product's TCB include the considerations and
activities identified by the development process and
operational support requirements of the protection profile.
Consumer confidence in the correspondence between the
protection profile requirements and the product's TCB is
greater when security analysis and the production of evidence
are done on a regular basis as a integral part of the
development process and operational support activities.
For CS3, LC-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
LC-1: Developer-Defined Life Cycle Process
The developer shall describe the process used to
develop and maintain the product. The process
shall incorporate a security policy that states
the technical, physical, procedural, personnel,
and other measures used by the developer to
protect the product and its documentation. The
developer shall trace each development process and
support process requirement of the protection
profile to the part, or parts, of the developer's
process where the requirement is satisfied. The
developer shall identify the programming languages
used to develop the TCB software.
4.11 Configuration Management
Configuration management is an assurance component that
ensures that the product's TCB configuration remains
consistent and complete, and that changes to the TCB do not
adversely affect the protection properties of the TCB.
Configuration management must ensure that additions,
deletions, or changes to the TCB do not compromise the
correspondence between the TCB's implementation and the
requirements of the protection profile. This is accomplished
by requiring the developer to have procedures or tools that
ensure that the TCB and its documents are updated properly
with the TCB changes.
For CS3, CM-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
CM-1: Procedural Control and Generation
The developer shall establish configuration
control and generation procedures for developing
and maintaining the TCB. The procedures shall be
employed to ensure that changes to the TCB are
consistent with the product's protection
properties and security policy. The developer
shall employ these procedures to track changes to
development evidence, implementation data (e.g.,
source code and hardware diagrams), executable
versions of the TCB, test documentation and
procedures, identified flaws, and consumer
documentation.
The configuration control procedures shall permit
the regeneration of any supported version of the
TCB.
4.12 Evidence of TCB Protection Properties
The documentation of the TCB protection properties includes
the definition of the functional component requirements,
their modeling (if any), and their interpretation within a
product's TCB. For each requirement of a protection profile,
a description, definition (an informal, descriptive
specification), or a formal specification of the TCB
components and their operation corresponding to the
requirement must be provided.
For CS3, EPP-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPP-2 Evidence of Informal Model Interpretation in the TCB
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. The developer shall also
provide an informal access control model and its
interpretation within the TCB. The TCB properties,
which are defined by this correspondence, shall be
explained in this documentation.
4.13 Evidence of Product Development
Product development evidence consists of the TCB design
evidence including the documentation of the TCB interface, TCB
elements, TCB structure, TCB structuring support, and TCB
design disciplines. The TCB implementation evidence includes
TCB source code, and the processor hardware and firmware
specifications.
For CS3, EPD-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPD-1: Description Of The TCB External Interface
The developer shall provide an accurate
description of the functions, effects, exceptions
and error messages visible at the TCB interface.
The developer shall provide a list of the TCB
elements (hardware, software, and firmware).
4.14 Evidence of Functional Testing
Functional testing evidence includes the testing itself,
the test plans, and test documentation results. Test plans
consist of: the description definition or specification of the
test conditions; the test data, which consists of the test
environment set-up; the test parameters and expected
outcomes; and a description of the test coverage.
For CS3, EFT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EFT-1: Evidence of Conformance Testing
The developer shall provide evidence of the
functional testing that includes the test plan,
the test procedures and the results of the
functional testing.
4.15 Evidence of Penetration Analysis
The penetration analysis evidence includes, in addition to
penetration test plans and results configured in the same
manner as the functional testing evidence, the documentation
of the penetration-resistance testing methods and tools,
conditions that were verified, the outcomes of the
verification and, when appropriate, the scenario of the
discovered penetration flaws. The cause of every discovered
penetration flaw, or class of penetration flaws, must also be
documented.
For CS3, EPA-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPA-1: Evidence of Penetration Testing
The developer shall provide evidence of
penetration testing. The evidence shall identify
all product documentation on which the search for
flaws was based. The penetration evidence shall
describe the scenarios for exploiting each
potential flaw in the system and the penetration
test conditions, data (e.g., test set-up, function
call parameters, and test outcomes), coverage, and
conclusions derived from each scenario.
4.16 Evidence of Product Support
Product support evidence consists of the development
environment and operational support documentation and tools.
The development environment evidence includes the
documentation of the product life-cycle process,
configuration management procedures enforced, and the trusted
distribution mechanisms and procedures used. It also
includes: the identification of the tools used in the product
development, configuration management, and trusted
distribution; and the characteristics that make those tools
suitable for the development of product protection.
For CS3, EPS-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
EPS-1: Evidence of Basic Product Support
The developer shall provide evidence that
describes the policies, procedures, and plans
established by the developer to satisfy the
Operational Support and Development Environment
requirements of the protection profile.
4.17 Test Analysis
Test analysis determines whether the product meets the
functional protection requirements defined in the protection
profile. Functional testing is based on operational product,
the TCB's functional properties, the product's operational
support guidance, and other producer's documentation as
defined by the development evidence requirements. Functional
test analysis is based on the achieved test results as
compared to the expected results derived from the development
evidence.
For CS3, TA-2 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
TA-2: Enhanced Test Analysis
The evaluator shall assess whether the producer
has performed the activities defined in the
development assurance requirements of the
protection profile for functional testing and
penetration analysis, and whether the producer has
documented these activities as defined in the
development evidence requirements of the
protection profile. The evaluator shall analyze
the results of the producer's testing activities
for completeness of coverage and consistency of
results, and general correctness (e.g., defect
trend from regression testing). This analysis
shall examine the testability of requirements, the
adequacy of the tests to measure the required
properties, the deviation of the actual results
obtained from the expected results, and a general
interpretation of what the testing results mean.
The evaluator shall determine whether the
product's protection properties, as described in
the product documentation, and all relevant known
penetration flaws have been tested. The evaluator
shall assess testing results to determine whether
the product's TCB works as claimed, and whether
there are any remaining obvious ways (i.e., ways
that are known, or that are readily apparent or
easily discovered in product documentation) for an
unauthorized user to bypass the policy implemented
by the TCB or otherwise defeat the product's TCB.
4.18 Independent Testing
Independent testing determines whether the product's TCB
meets the functional protection requirements as defined in the
functionality chapter of this Protection Profile. Testing is
based on operational product, the TCB's functional
properties, the product's operational support guidance, and
other producer's documentation as defined by the Development
Evidence requirements.
For CS3, IT-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
IT-1: Elementary Independent Testing
A tester, independent of the producer or
evaluator, shall perform functional and elementary
penetration testing. This testing shall be based
on the product's user and administrative
documentation, and on relevant known penetration
flaws. Satisfactory completion consists of
demonstrating that all user-visible security
enforcing functions and security-relevant
functions work as described in the product's user
and administrative documentation and that no
discrepancies exist between the documentation and
the product. Test results of the producer shall be
confirmed by the results of independent testing.
The evaluator may selectively reconfirm any test
result.
If the independent testing is performed at beta-
test sites, the producer shall supply the beta-
test plan and the test results. The evaluator
shall review the scope and depth of beta testing
with respect to the required protection
functionality, and shall verify independence of
both the test sites and the producer's and beta-
test user's test results. The evaluator shall
confirm that the test environment of the beta-test
site(s) adequately represents the environment
specified in the protection profile.
4.19 Development Environment Review
Development environment review determines whether the
product meets the requirements as defined in the protection
profile's Development Assurance subsections for Development
Environment including Life-Cycle Definition and Configuration
Management.
For CS3, DER-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
DER-1: Elementary Development Environment Review
The evaluator shall review the producer's
development and maintenance process description
documentation to determine the degree of
discipline enforced upon and within the process,
and to determine the protection characteristics
associated with the product's development and
maintenance. The results of this review shall
establish, for the evaluator, the producer's
development environment, its policies, and the
degree of enforcement maintained during
development execution.
4.20 Operational Support Review
Operation support review establishes the level of review
required to determine whether the product meets the
requirements as defined in the protection profile's
Development Assurance subsections for Operational Support
including, at the CS3 level, the User and Administrative
Guidance documents.
For CS3, OSR-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
OSR-1 Elementary Operational Support Review
The evaluator shall review all documentation
focused on the activities of product use (e.g.,
Users Manuals) and product administration
including installation, operation, maintenance,
and trusted recovery (e.g., Trusted Facility
Management Manuals). This review shall assess the
clarity of presentation, difficulty in locating
topics of interest, ease of understanding, and
completeness of coverage. The need for separate
manuals dedicated to protection-relevant aspects
of the product should be assessed for
effectiveness.
This component should also address flaw
remediation and trusted generation. [[TBD.]]
4.21 Design Analysis
Design analysis determines whether the product meets the
design requirements as defined in the Development Process
Assurance section of the protection profile, including the TCB
Property Definition and TCB Design requirements. The analysis
is based on the producer's documentation, as defined by the
Development Evidence requirements.
For CS3, DA-1 was assigned from the Federal Criteria. No
refinements were made from the Federal Criteria.
DA-1: Elementary Design Analysis
The evaluator shall determine whether the producer
has performed the activities defined in the
development process assurance requirements of the
protection profile for TCB property definition and
TCB design. The evaluator shall determine whether
the producer has documented these activities as
defined in the development evidence requirements
of the protection profile. The evaluator shall
analyze the results of the producer's activities
for completeness and consistency of design with
respect to requirements.
CSR References
1. U.S. Department of Defense Trusted Computer System
Evaluation Criteria (TCSEC), DoD 5200.28-STD, December
1985.
2. Information Technology Security Evaluation Criteria
(ITSEC) - Provisional Harmonized Criteria, Version 1.2,
June 1991.
3. Bellcore Standard Operating Environment Security
Requirements, TA-STS-001080, Issue 2, June, 1991.
4. Commercial International Security Requirements (CISR),
Cutler, K. and Jones, F., Final Draft, September 9, 1991.
5. Computers at Risk - Safe Computing in the Information
Age, National Research Council, National Academy Press,
1991.
6. Information Technology - Open Systems Interconnection -
Security Frameworks in Open Systems - Part 2:
Authentication Framework, Draft International Standard
DIS 10181-2, International Organization for
Standardization, 13 May 1991
7. Assessing Federal and Commercial Information Security
Needs, Ferraiolo, D., Gilbert, D., and Lynch, N., NIST
Draft Internal Report, September 1992.
8. Security Controls for Computer Systems: Report of Defense
Science Board Task Force on Computer Security, Willis
Ware, Editor, R-609-1, 1970, Reissued October 1979.
9. Information Processing Systems - Open Systems
Interconnection Reference Model - Part 2: Security
Architecture, International Standard ISO 7498-2,
International Organization for Standardization, 1988
10. Minimum Security Requirements for Multi-User Operating
Systems: A Protection Profile for the U.S. Information
Security Standard, National Institute of Standards and
Technology, 1992 draft.
11. U.S. Information Technology Security Standard.
12. Role-Based Access Controls, Ferraiolo, D. and Kuhn, R.,
15th National Computer Security Conference, October 1992.
13. A Comparison of Commercial and Military Computer
Security Policies, IEEE Symposium on Computer Security and
Privacy, April 1987.
DRAFT
LABEL BASED PROTECTION
FOR
MULTI-USER INFORMATION SYSTEMS
LEVEL 1
(LP-1)
A Protection Profile
Derived from the Federal Criteria for IT Security
Version 1.0
December 1992
This document is undergoing review and
is subject to modification or withdrawal.
The contents of this document should not
be referenced in other publications.
Supersedes the
Trusted Computer System Evaluation Criteria
Class B1
DRAFT
LABEL-BASED PROTECTION - 1 (LP-1)
This Protection Profile has been developed to define a set of
technical measures that can be incorporated into remote-
access, resource- and information-sharing Information
Technology (IT) products that will be used to protect two or
more compartments of National Security Information classified
according to US Executive Order 12356 (EO 12356). This profile
can also be used to protect any information that has been
designated as sensitive information for which information
separation and access are based on sensitivity markings
applied to the information.
Compliant IT products will provide protection for a
compartmented information processing environment with which
an organization can construct an automated information system
to enhance or optimize the organization's ability to perform
its mission.
In LP-1 conformant systems, the TCB is based on a multi-level
security policy model for confidentiality that requires both
discretionary and non-discretionary access controls. In
relation to lower levels of protection functionality, LP-1
conformat systems have the following additional features.
a. Access control enforcement includes a defined subset
of subjects and objects in the ADP system.
b. An informal statement of the security policy model,
data labeling, and mandatory access control over named
subjects and objects is included.
c. The supported labels accurately represent the
sensitivity of objects and subjects, and are
maintained on exported objects.
d. Any flaws identified by testing are removed or
neutralized.
Cross References:
o Existing Criteria:
(1) TCSEC: B1
(2) ITSEC
(3) CTCPEC
o Other Protection Profiles
(1) TBD
COMPONENT SUMMARY:
LP-1 Functional Component Summary
.--------------------------------------------.
| | Code & |
| Functional Component | Level |
|============================================|
| Security Policy Support |
|----------------------------------+---------|
| Accountability | |
|----------------------------------+---------|
| Identification&Authentication | I&A-2 |
|----------------------------------+---------|
| System Entry | ---- |
|----------------------------------+---------|
| Trusted Path | ---- |
|----------------------------------+---------|
| Audit | AD-1 |
|----------------------------------+---------|
| Access Control | AC-2 |
|----------------------------------+---------|
| Discretionary | AC-2 |
|----------------------------------+---------|
| Non-Discretionary | AC-2 |
|----------------------------------+---------|
| Covert Channel Handling | ----- |
|----------------------------------+---------|
| Availability | ---- |
|----------------------------------+---------|
| Resource Allocation | ---- |
|----------------------------------+---------|
| Fault Tolerance | ---- |
|----------------------------------+---------|
| Security Mgmt. | ---- |
|----------------------------------+---------|
| Reference Mediation | RM-1 |
|----------------------------------+---------|
| TCB Logical Protection | P-1 |
|----------------------------------+---------|
| TCB Physical Protection | ---- |
|----------------------------------+---------|
| TCB Self-checking | SC-1 |
|----------------------------------+---------|
| TCB Start-Up and Recovery | ---- |
|----------------------------------+---------|
| TCB Privileged Operation | ---- |
|----------------------------------+---------|
| TCB Ease-of-Use | ---- |
`--------------------------------------------'
LP-1 Assurance Component Summary
.---------------------------------------.
| Assurance Components | T2 |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-2 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-1 |
|--------------------------------+------|
| TCB Modular Decomposition | ---- |
|--------------------------------+------|
| TCB Structuring Support | SP-1 |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | ---- |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-1 |
|--------------------------------+------|
| Trusted Generation | TG-1 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | ---- |
|--------------------------------+------|
| Configuration Management | ---- |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP2 |
|--------------------------------+------|
| Product Development | EPD1 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT1 |
|--------------------------------+------|
| Penetration Analysis | ---- |
|--------------------------------+------|
| Covert Channel Analysis | ---- |
|--------------------------------+------|
| Product Support | EPS1 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-1 |
|--------------------------------+------|
| Independent Testing | IT-1 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | ---- |
|--------------------------------+------|
| Operational Support | OSR1 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | ---- |
|--------------------------------+------|
| Implementation | ---- |
`---------------------------------------'
RATIONALE
1. Information Protection Policy
It is anticipated that organizations wishing to process
compartmented-mode classified information will want to use IT
products that are compliant with this profile in their
automated information processing systems. These organizations
should be able to trust the profile-compliant IT product to
contribute to the protection of the compartmented information
at least as much as they trust the properly cleared personnel
who are using and managing the system.
2. Protection Philosophy
This profile presumes an environment providing control of
access to shared resources both (1) on the basis of attributes
that are controlled by the ordinary users of the system and
(2) on the basis of attributes that are controlled only by the
system administrators.
Profile compliant IT products will minimally meet the
following objectives:
a. Enforce an informally defined security policy that
describes the rules for accessing and administering
access controls.
b. Associate explicit sensitivity labels with a defined
subset of the system entities. Associate explicit
sensitivity labels with each port through which
information may be exported from or imported to the
system. Maintain the accuracy of the access control
labels as information moves within the system and
through the ports.
c. Authenticate the claimed identity of each external
human user of the IT product prior to establishing any
internal entity to act on behalf of that user and
firmly bind the authenticated user identity to the
internal entity.
d. Selectively keep and protect a log of all actions or
events that could affect system security so that they
can be accurately attributed to the known user or
system entity responsible for causing the action or
event.
3. Expected Threats
The requirements for profile conforming IT products assume
that these products are being used in an environment where
there are multiple categories of classified data and users. A
conforming IT product can be expected to protect the
confidentiality of information in an environment where there
are two or more levels of classified data and two or more
levels of cleared users, but where malicious applications
programs (e.g., Trojan Horses) and users are not present.
4. Assumed Environment
4.1 Characteristics
IT products complying with the requirements set forth in this
profile are expected to be used in an environment with the
following characteristics:
a. Multiple users will be accessing the operating system
at the same time.
b. The IT product hardware base (e.g., CPU, printers,
terminals, etc.) is protected from unauthorized
physical access.
c. One or more administrators are assigned to manage the
system in which the IT product is incorporated,
including the security of the information it contains.
d. A need to control user access to objects exists and is
based on an explicit sensitivity marking associated
with the information (e.g, Confidential, Secret or Top
Secret) and on that user's identity and membership in
organizations or groups.
e. The IT product provides facilities for some or all of
the authorized users to create programs that use the
applications programming interface (API) and make
those programs available to other users.
f. The IT product is used to provide a cooperative
environment for the users to accomplish some task or
group of tasks.
4.2 Environment Dependencies
Secure installation and operation of a product satisfying
these profile requirements depends on provision of a number
of elements in the installation environment. These include:
a. Physical security must be provided.
b. Cabling to other devices must be shown to be
consistent with policy implemented by the product. For
example, a "port" in the product is required to have
an assigned label. No device can be connected to the
port unless it has been established externally that
the device is allowed to receive data with the same
label.
c. Personnel allowed to access data processed by the
installed product must already be authorized for such
access.
5. Intended Use
Conforming IT products are useful in both general-purpose
office automation environments with multiple data
sensitivities and in specialized computing, network and
mission environments. Examples of the office automation
environment might include military headquarters and highly
competitive procurement offices. An example of the
specialized mission environment might be as a platform for a
portable battlefield map and mission management application.
FUNCTIONAL REQUIREMENTS
I&A-2 Identification, Authentication, and Authorization
1. The TCB shall require users to identify
themselves to it before beginning to perform any
other actions that the TCB is expected to mediate.
The TCB shall be able to enforce individual
accountability by providing the capability to
uniquely identify each individual user. The TCB
shall also provide the capability of associating
this identity with all auditable actions taken by
that individual.
2. The TCB shall maintain authentication data that
includes information for verifying the identity of
individual users (e.g., passwords) as well as
information for determining the clearance and
authorization of individual users. These data
shall be used by the TCB to authenticate the
user's identity and to ensure that the subject
security level and authorizations of subjects
external to the TCB that may be created to act on
behalf of the individual user are dominated by the
clearance and authorization of that user).
3. The TCB shall protect authentication data so
that it cannot be used by any unauthorized user.
AD-1 - Minimal Audit
1. The TCB shall be able to create, maintain, and
protect from modification or unauthorized access
or destruction an audit trail of accesses to the
objects it protects. The audit data shall be
protected by the TCB so that read access to it is
limited to those who are authorized for audit
data.
2. The TCB shall be able to record the following
types of events:
- use of the identification and authentication
mechanisms;
- introduction of objects into a user's address
space (e.g., file open, program initiation), and
deletion of objects;
- actions taken by computer operators and system
administrators and/or system security officers.
The TCB shall be able to record any override of
human-readable output markings.
3. For each recorded event, the audit record shall
identify: date and time of the event, user, type
of event, and success or failure of the event. For
identification/authentication events the origin of
request (e.g., terminal ID) shall be included in
the audit record. For events that introduce an
object into a user's address space and for object
deletion events the audit record shall include the
name and the object security level.
4. The system administrator shall be able to
selectively audit the actions of one or more users
based on individual identity and/or object
security level.
AC-2 Basic Access Control
1. Definition of Access Control Attributes
The TCB shall define and protect access control
attributes for subjects and objects. Subject
attributes shall include named individuals or
defined groups or both. Object attributes shall
include defined access rights (e.g., read, write,
execute) that can be assigned to subject
attributes. Access control attributes
corresponding to each individual policy shall be
identified.
Sensitivity labels associated with each subject
and object shall be maintained by the TCB. The
sensitivity labels shall be used as the basis for
mandatory access control decisions.
The subjects and objects shall be assigned
sensitivity labels that are a combination of
hierarchical classification levels and non-
hierarchical categories, and the labels shall be
used as the basis for mandatory access control
decisions. The TCB shall be able to support two or
more such security levels.
The subject and object attributes shall accurately
reflect the sensitivity and integrity of the
subject or object. When exported by the TCB,
sensitivity labels shall accurately and
unambiguously represent the internal labels and
shall be associated with the information being
exported.
2. Administration of Access Control Attributes
The TCB shall define and enforce rules for
assignment and modification of access control
attributes for subjects and objects. The effect of
these rules shall be that access permission to an
object by users not already possessing access
permission is assigned only by authorized users.
These rules shall allow authorized users to
specify and control sharing of objects by named
individuals or defined groups of individuals, or
by both, and shall provide controls to limit
propagation of access rights. These controls shall
be capable of including or excluding access to the
granularity of a single user.
The rules for assignment and modification of
access control attributes shall include those for
attribute assignment to objects during import and
export operations.
Export of Labeled Information
The TCB shall designate each communication
channel and I/O device as either single-level or
multilevel. Any change in this designation shall
be done manually and shall be auditable by the
TCB. The TCB shall maintain and be able to audit
any change in the security level or levels
associated with a communication channel or I/O
device.
1. Exportation to Multilevel Devices
When the TCB exports an object to a multilevel
I/O device, the sensitivity label associated with
that object shall also be exported and shall
reside on the same physical medium as the exported
information and shall be in the same form (i.e.,
machine-readable or human-readable form). When the
TCB exports or imports an object over a multilevel
communication channel, the protocol used on that
channel shall provide for the unambiguous pairing
between the sensitivity labels and the associated
information that is sent or received.
2. Exportation to Single-Level Devices
Single-level I/O devices and single-level
communication channels are not required to
maintain the sensitivity labels of the information
they process. However, the TCB shall include a
mechanism by which the TCB and an authorized user
reliably communicate to designate the single
security level of information imported or exported
via single-level communication channels or I/O
devices.
3. Labeling Human-Readable Output
The system administrator shall be able to
specify the printable label names associated with
exported sensitivity labels. The TCB shall mark
the beginning and end of all human-readable,
paged, hardcopy output (e.g., line printer output)
with human-readable sensitivity labels that
properly represent the sensitivity of the output.
The TCB shall, by default, mark the top and bottom
of each page of human-readable, paged, hardcopy
output (e.g., line printer output) with human-
readable sensitivity labels that properly
represent the overall sensitivity of the output or
that properly represent the sensitivity of the
information on the page. The TCB shall, by default
and in an appropriate manner, mark other forms of
human-readable output (e.g., maps, graphics) with
human-readable sensitivity labels that properly
represent the sensitivity of the output. Any
override of these marking defaults shall be
auditable by the TCB.
Import of Non-labeled Data
In order to import non-labeled data, the TCB
shall request and receive from an authorized user
the security level of the data, and all such
actions shall be auditable by the TCB.
If different rules of assignment and modification
of access control attributes apply to different
subjects and/or objects, the totality of these
rules shall be shown to support the defined
policy.
3. Authorization of Subject References to Objects
The TCB shall define and enforce authorization
rules for the mediation of subject references to
objects. These rules shall be based on the access
control attributes of subjects and objects. These
rules shall, either by explicit user action or by
default, provide that objects are protected from
unauthorized access.
The authorization rules for the mandatory access
control policy shall include:
The TCB shall enforce a mandatory access control
policy over all subjects and storage objects under
its control (e.g., processes, files, segments,
devices). The following requirements shall hold
for all accesses between all subjects and objects
controlled by the TCB: A subject can read an
object only if the hierarchical classification in
the subject's security level is greater than or
equal to the hierarchical classification in the
object's security level and the non- hierarchical
categories in the subject's security level include
all the non-hierarchical categories in the
object's security level. A subject can write an
object only if the hierarchical classification in
the subject's security level is less than or equal
to the hierarchical classification in the object's
security level and all the non-hierarchical
categories in the subject's security level are
included in the non-hierarchical categories in the
object's security level.
The scope of the authorization rules shall include
a defined subset of the product's subjects and
objects and associated access control attributes.
The coverage of authorization rules shall specify
the types of objects and subjects to which these
rules apply. If different rules apply to different
subjects and objects, the totality of these rules
shall be shown to support the defined policy.
The authorization rules for each policy shall be
defined separately. The TCB shall define and
enforce the composition of policies, including the
enforcement of the authorization rules (e.g.,
subject and object type coverage, enforcement
precedence).
4. Subject and Object Creation and Destruction
The TCB shall control the creation and destruction
of subjects and objects. These controls shall
include object reuse. That is, all authorizations
to the information contained within a storage
object shall be revoked prior to initial
assignment, allocation or reallocation to a
subject from the TCB's pool of unused storage
objects; information, including encrypted
representations of information, produced by a
prior subjects' actions shall be unavailable to
any subject that obtains access to an object that
has been released back to the system.
RM-1 Mediation of References to a Defined Subject/Object
Subset
1. The TCB shall mediate all references to
subjects, objects, resources, and services (e.g.,
TCB functions) described in the TCB
specifications. The mediation shall ensure that
all references are directed to the appropriate
security-policy functions.
2. Reference mediation shall include references to
the defined subset of subjects, objects, and
resources protected under the TCB security policy,
and to their policy attributes (i.e., access
rights, security levels).
3. References issued by privileged subjects shall
be mediated in accordance with the policy
attributes defined for those subjects.
P-1 Basic TCB Isolation
The TCB shall maintain a domain for its own
execution that protects it from external
interference and tampering (e.g., by reading or
modification of its code and data structures). The
protection of the TCB shall provide TCB isolation
and noncircumventability of TCB isolation
functions as follows:
1. TCB Isolation requires that (1) the address
spaces of the TCB and those of unprivileged
subjects are separated such that users, or
unprivileged subjects operating on their behalf,
cannot read or modify TCB data structures or code,
(2) the transfers between TCB and non-TCB domains
are controlled such that arbitrary entry to or
return from the TCB are not possible; and (3) the
user or application parameters passed to the TCB
by addresses are validated with respect to the TCB
address space, and those passed by value are
validated with respect to the values expected by
the TCB.
2. Noncircumventability of TCB isolation
functions requires that the permission to objects
(and/or to non-TCB data) passed as parameters to
the TCB are validated with respect to the
permissions required by the TCB, and references to
TCB objects implementing TCB isolation functions
are mediated by the TCB.
SC-1 Minimal Self Checking
Hardware and/or software features shall be
provided that can be used to periodically validate
the correct operation of the on-site hardware and
firmware elements of the TCB.
ASSURANCES
Requirements for TCB Property Definition
PD-2 Informal Property Identification
The developer shall provide informal models for
the functional components and sub-components of
the profile. At a minimum, an informal model of
the access control components shall be provided.
Each informal model shall include (abstract) data
structures and operations defining each functional
component or sub-component, and a description of
the model properties. The developer shall
interpret (e.g., trace) the informal models within
the product TCB. For each model entity, the
developer shall: (1) identify the TCB elements and
their TCB interfaces (if any) that implement that
entity; (2) define the operation of these TCB
elements, and (3) explain why the operation of
these elements is consistent with the model
properties. The developer's interpretation of each
informal model, which defines the TCB properties,
shall identify all TCB elements that do not
correspond to any model entity and shall explain
why these elements do not render the TCB
properties invalid.
For the components that are not informally
modeled, the developer shall interpret the
functional requirements of the protection profile
within the product TCB. For each functional
requirement, the developer shall: (1) identify the
TCB elements and their TCB interfaces (if any)
that implement that requirement; (2) describe the
operation of these TCB elements, and (3) explain
why the operation of these elements is consistent
with the functional requirement. The developer's
interpretation of each functional requirement,
which describes the TCB properties, shall identify
all TCB elements that do not correspond to any
functional requirement and shall explain why these
elements do not render the TCB properties invalid.
Requirements for TCB Element Identification
ID-2: TCB Element Justification
The developer shall identify the TCB elements
(i.e., software, hardware/firmware code and data
structures). Each element must be unambiguously
identified by its name, type, release, and version
number (if any).
The developer shall justify the protection
relevance of the identified elements (i.e., only
elements that can affect the correct operation of
the protection functions shall be included in the
TCB).
Requirements for TCB Interface Definition
IF-1: Interface Description
The developer shall describe all external (e.g.,
command, software, and I/O) administrative (i.e.,
privileged) and non-administrative interfaces to
the TCB. The description shall include those
components of the TCB that are implemented as
hardware and/or firmware if their properties are
visible at the TCB interface.
The developer shall identify all call conventions
(e.g., parameter order, call sequence
requirements) and exceptions signaled at the TCB
interface.
Requirements for TCB Structuring Support
SP-1: Process Isolation
The TCB shall maintain process isolation.
Requirements for Developer Functional Testing
FT-1: Conformance Testing
The developer shall test the TCB interface to show
that all claimed protection functions work as
stated in the TCB interface description.
The developer shall correct all flaws discovered
by testing and shall retest the TCB until the
protection functions are shown to work as claimed.
Requirements for User Guidance
UG-1: Users' Guide
The developer shall provide a User Guide which
describes all protection services provided and
enforced by the TCB. The User Guide shall describe
the interaction between these services and provide
examples of their use. The User Guide may be in the
form of a summary, chapter or manual. The User
Guide shall specifically describe user
responsibilities. These shall encompass any user
responsibilities identified in the protection
profile.
Requirements for Administrative Guidance
AG-1: Basic Administrative Guidance
The developer shall provide a Trusted Facility
Manual intended for the product administrators
that describes how to use the TCB security
services (e.g., Access Control, System Entry, or
Audit) to enforce a system security policy. The
Trusted Facility Manual shall include the
procedures for securely configuring, starting,
maintaining, and halting the TCB. The Trusted
Facility Manual shall explain how to analyze audit
data generated by the TCB to identify and document
user and administrator violations of this policy.
The Trusted Facility Manual shall explain the
privileges and functions of administrators. The
Trusted Facility Manual shall describe the
administrative interaction between security
services.
The Trusted Facility Manual shall be distinct from
User Guidance, and encompass any administrative
responsibilities identified in security
management.
Requirements for Trusted Generation
TG-1: Basic Trusted Generation
The developer shall establish and document the
procedures that a consumer must perform to
generate an operational TCB from the delivered
copy of the master TCB. The consumer documentation
shall identify any system parameters, which are
initialized or set during system generation, that
affect the TCB's conformance to the protection
profile and state the acceptable ranges of values
for those parameters.
Requirements for Evidence of TCB Protection Properties
EPP-2 Evidence of Informal Model Interpretation in the TCB
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. The developer shall also
provide an informal access control model and its
interpretation within the TCB. The TCB properties,
which are defined by this correspondence, shall be
explained in this documentation.
Requirements for Evidence of Product Development
EPD-1: Description Of The TCB External Interface
The developer shall provide an accurate
description of the functions, effects, exceptions
and error messages visible at the TCB interface.
The developer shall provide a list of the TCB
elements (hardware, software, and firmware).
Requirements for Evidence of Functional Testing
EFT-1: Evidence of Conformance Testing
The developer shall provide evidence of the
functional testing that includes the test plan,
the test procedures and the results of the
functional testing.
Requirements for Evidence of Product Support
EPS-1: Evidence of Basic Product Support
The developer shall provide evidence that
describes the policies, procedures, and plans
established by the developer to satisfy the
Operational Support and Development Environment
requirements of the protection profile.
Requirements for Test Analysis
TA-1: ElementaryTest Analysis
The evaluator shall assess whether the producer
has performed the activities defined in the
development assurance requirements of the
protection profile for functional testing and
whether the producer has documented these
activities as defined in the development evidence
requirements of the protection profile. The
evaluator shall analyze the results of the
producer's testing activities for completeness of
coverage and consistency of results. The evaluator
shall determine whether the product's protection
properties, as described in the product
documentation have been tested. The evaluator
shall assess testing results to determine whether
the product's TCB works as claimed.
Requirements for Independent Testing
T-1: Elementary Independent Testing
A tester, independent of the producer or
evaluator, shall perform functional and elementary
penetration testing. This testing shall be based
on the product's user and administrative
documentation, and on relevant known penetration
flaws. Satisfactory completion consists of
demonstrating that all user-visible security
enforcing functions and security-relevant
functions work as described in the product's user
and administrative documentation and that no
discrepancies exist between the documentation and
the product. Test results of the producer shall be
confirmed by the results of independent testing.
The evaluator may selectively reconfirm any test
result.
If the independent testing is performed at beta-
test sites, the producer shall supply the beta-
test plan and the test results. The evaluator
shall review the scope and depth of beta testing
with respect to the required protection
functionality, and shall verify independence of
both the test sites and the producer's and beta-
test user's test results. The evaluator shall
confirm that the test environment of the beta-test
site(s) adequately represents the environment
specified in the protection profile.
Requirements for Operational Support Review
OSR-1 Elementary Operational Support Review
The evaluator shall review all documentation
focused on the activities of product use (e.g.,
Users Manuals) and product administration
including installation, operation, maintenance,
and trusted recovery (e.g., Trusted Facility
Management Manuals). This review shall assess the
clarity of presentation, difficulty in locating
topics of interest, ease of understanding, and
completeness of coverage. The need for separate
manuals dedicated to protection-relevant aspects
of the product should be assessed for
effectiveness.
DRAFT
LABEL BASED PROTECTION
FOR
MULTI-USER INFORMATION SYSTEMS
LEVEL 2
(LP-2)
A Protection Profile
Derived from the Federal Criteria for IT Security
Version 1.0
December 1992
This document is undergoing review and
is subject to modification or withdrawal.
The contents of this document should not
be referenced in other publications.
Supersedes the
Trusted Computer System Evaluation Criteria
Class B2
DRAFT
LABEL-BASED PROTECTION - 2 (LP-2)
This Protection Profile has been developed to define a set
of technical measures that can be incorporated into remote-
access, resource- and information-sharing Information
Technology (IT) products that will be used to protect up to
three levels or more than two categories of National Security
Information classified according to US Executive Order 12356
(EO 12356). This profile can also be used to protect any
information that has been designated as sensitive information
for which information separation and access are based on
sensitivity markings applied to the information.
Compliant IT products will provide structured protection
for a multi-level information processing environment with
which an organization can construct an automated information
system to enhance or optimize the organization's ability to
perform its mission.
In LP-2 conformant systems, the TCB is based on a clearly
defined and documented formal security policy model for
confidentiality that requires both discretionary and non-
discretionary access controls. Also, The TCB is relatively
resistant to penetration. In relation to lower levels of
protection functionality, LP-2 conformat systems have the
following additional features.
a. Access control enforcement is extended to all subjects
and objects in the ADP system.
b. Covert storage channels are identified and handled.
c. The TCB is modularized and carefully structured into
protection-critical and non-protection-critical.
d. The TCB interface is well-defined and the TCB design
and implementation enables it to be subjected to
thorough testing and review. Penetration testing is
also performed, and the TCB must be found relatively
resistant to penetration.
e. Authentication mechanisms cover all policy attributes
of a user (e.g., groups, secrecy and/or integrity
levels, roles), not just the individual identity.
f. Security management is enhanced by the separation of
system administrator and operator functions.
g. Configuration management controls are imposed.
Cross References:
o Existing Criteria:
(1) TCSEC: B2
(2) ITSEC
(3) CTCPEC
o Other Protection Profiles
(1) TBD
COMPONENT SUMMARY:
LP-2 Functional Component Summary
.--------------------------------------------.
| | Code & |
| Functional Component | Level |
|============================================|
| Security Policy Support |
|----------------------------------+---------|
| Accountability | |
|----------------------------------+---------|
| Identification uthentication | I&A-2 |
|----------------------------------+---------|
| System Entry | ---- |
|----------------------------------+---------|
| Trusted Path | TP-1 |
|----------------------------------+---------|
| Audit | AD-1 |
|----------------------------------+---------|
| Access Control | AC-3 |
|----------------------------------+---------|
| Discretionary | AC-3 |
|----------------------------------+---------|
| Non-Discretionary | AC-3 |
|----------------------------------+---------|
| Covert Channel Handling | CCH-2 |
|----------------------------------+---------|
| Availability | ---- |
|----------------------------------+---------|
| Resource Allocation | ---- |
|----------------------------------+---------|
| Fault Tolerance | ---- |
|----------------------------------+---------|
| Security Mgmt. | SM-1+ |
|----------------------------------+---------|
| Reference Mediation | RM-3 |
|----------------------------------+---------|
| TCB Logical Protection | P-2 |
|----------------------------------+---------|
| TCB Physical Protection | ---- |
|----------------------------------+---------|
| TCB Self-checking | SC-1 |
|----------------------------------+---------|
| TCB Start-Up and Recovery | ---- |
|----------------------------------+---------|
| TCB Privileged Operation | PO-2 |
|----------------------------------+---------|
| TCB Ease-of-Use | ---- |
`--------------------------------------------'
LP-2 Assurance Component Summary
.---------------------------------------.
| Assurance Components | T5 |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-3 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-2 |
|--------------------------------+------|
| TCB Modular Decomposition | MD-2 |
|--------------------------------+------|
| TCB Structuring Support | SP-2 |
|--------------------------------+------|
| TCB Design Disciplines | ---- |
|--------------------------------+------|
| TCB Implementation Support | IM-3 |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-3 |
|--------------------------------+------|
| Penetration Analysis | PA-2 |
|--------------------------------+------|
| Covert Channel Analysis | CCA1 |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-2 |
|--------------------------------+------|
| Trusted Generation | TG-2 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | LC-2 |
|--------------------------------+------|
| Configuration Management | CM-2 |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP3 |
|--------------------------------+------|
| Product Development | EPD3 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT3 |
|--------------------------------+------|
| Penetration Analysis | EPA2 |
|--------------------------------+------|
| Covert Channel Analysis | ECC1 |
|--------------------------------+------|
| Product Support | EPS2 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-4 |
|--------------------------------+------|
| Independent Testing | IT-3 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | DER2 |
|--------------------------------+------|
| Operational Support | OSR2 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | DA-2 |
|--------------------------------+------|
| Implementation | CI-1 |
`---------------------------------------'
RATIONALE
6. Information Protection Policy
It is anticipated that organizations wishing to process
either one level with three or more categories or one to three
levels with one category of classified information will want
to use IT products that are compliant with this profile in
their automated information processing systems. These
organizations should be able to trust the profile-compliant
IT product to contribute to the protection of the classified
information at least as much as they trust the properly
cleared personnel who are using and managing the system.
7. Protection Philosophy
This profile presumes a hostile environment with divided,
aggressive users. It provides control of access to shared
resources both (1) on the basis of attributes that are
controlled by the ordinary users of the system and (2) on the
basis of attributes that are controlled only by the system
administrators.
Profile compliant IT products will minimally meet the
following objectives:
a. Enforce a formally defined security policy that
describes the rules for controlling access to system
subjects and objects. Use the access control rules to
enforce an information flow policy that aims to
control the use of covert storage channels.
b. Associate explicit sensitivity labels with each
subject and object in the system. Associate explicit
sensitivity labels with each port through which
information may be exported from or imported to the
system. Maintain the accuracy of the sensitivity
labels as information moves within the system and
through the ports.
c. Authenticate the claimed identity of each external
human user of the IT product prior to establishing any
internal entity to act on behalf of that user and
firmly bind the authenticated user identity to the
internal entity.
d. Selectively keep and protect a log of all actions or
events (including use of covert storage channels) that
could affect system security so that they can be
accurately attributed to the known user or system
entity responsible for causing the action or event.
e. Contains hardware and software mechanisms that can be
independently evaluated to provide sufficient
assurance that the system satisfies the previous four
objectives.
f. Implements the enforcement of objectives in such a
fashion that the enforcing mechanisms are protected
from tampering and unauthorized changes by the
entities these mechanisms are supposed to control.
8. Expected Threats
The requirements for profile conforming IT products assume
that these products are being used in an environment where
there are different levels or categories of classified data
and users of differing clearance levels. A conforming IT
product can be expected to protect the confidentiality of
information in an environment where there are two levels or
categories of classified data and two or more levels of
cleared users and where there are collaborating, malicious
users and software at each clearance level.
9. Assumed Environment
9.1 Characteristics
IT products complying with the requirements set forth in
this profile are expected to be used in an environment with
the following characteristics:
a. Multiple users will be accessing the operating system
at the same time.
b. The IT product hardware base (e.g., CPU, printers,
terminals, etc.) is protected from unauthorized
physical access.
c. One or more administrators are assigned to manage the
system in which the IT product is incorporated,
including the security of the information it contains.
d. A need to control user access to information exists
and is based on an explicit sensitivity marking
associated with the information (e.g, Secret or Top
Secret).
e. A need to control user access to all subjects and
objects exists and is based on that user's identity
and membership in organizations or groups.
f. The IT product provides facilities for some or all of
the authorized users to create programs that use the
applications programming interface (API) and make
those programs available to other users.
g. The IT product is used to provide a cooperative
environment for the users to accomplish some task or
group of tasks.
9.2 Environment Dependencies
Secure installation and operation of a product satisfying
these profile requirements depends on provision of a number
of elements in the installation environment. These include:
a. Physical security must be provided.
b. Cabling to other devices must be shown to be
consistent with policy implemented by the product. For
example, a "port" in the product is required to have
an assigned label. No device can be connected to the
port unless it has been established externally that
the device is allowed to receive data with the same
label.
c. Personnel allowed to access data processed by the
installed product must already be authorized for such
access.
10. Intended Use
Conforming IT products are useful in both general-purpose
office automation environments with multiple data
sensitivities (or "classifications") and multiple levels of
user authorizations (or "clearances") and in specialized
computing, network and mission environments. Examples of the
office automation environment might include military
headquarters and highly competitive procurement offices.
Examples of the network environments include use as the basis
for a multilevel secure network management center or a trusted
guard gateway operating between two networks processing
different levels of information. An example of the specialized
mission environment might be as a platform for a portable
battlefield map and mission management application.
FUNCTIONAL REQUIREMENTS
I&A-2 Identification, Authentication, and Authorization
1. The TCB shall require users to identify
themselves to it before beginning to perform any
other actions that the TCB is expected to mediate.
The TCB shall be able to enforce individual
accountability by providing the capability to
uniquely identify each individual user. The TCB
shall also provide the capability of associating
this identity with all auditable actions taken by
that individual.
2. The TCB shall maintain authentication data that
includes information for verifying the identity of
individual users (e.g., passwords) as well as
information for determining the clearance and
authorization of individual users. These data
shall be used by the TCB to authenticate the
user's identity and to ensure that the subject
security level and authorizations of subjects
external to the TCB that may be created to act on
behalf of the individual user are dominated by the
clearance and authorization of that user).
3. The TCB shall protect authentication data so
that it cannot be used by any unauthorized user.
TP-1 Login Trusted Path
The TCB shall support a trusted communication path
between itself and the user for initial
identification and authentication. Communications
via this path shall be initiated exclusively by a
user.
AD-1 - Minimal Audit
1. The TCB shall be able to create, maintain, and
protect from modification or unauthorized access
or destruction an audit trail of accesses to the
objects it protects. The audit data shall be
protected by the TCB so that read access to it is
limited to those who are authorized for audit
data.
2. The TCB shall be able to record the following
types of events:
- use of the identification and authentication
mechanisms;
- introduction of objects into a user's address
space (e.g., file open, program initiation), and
deletion of objects;
- actions taken by computer operators and system
administrators and/or system security officers.
The TCB shall be able to record any override of
human-readable output markings. The TCB shall also
be able to audit the identified event that may be
used in the exploitation of covert channels.
3. For each recorded event, the audit record shall
identify: date and time of the event, user, type
of event, and success or failure of the event. For
identification/authentication events the origin of
request (e.g., terminal ID) shall be included in
the audit record. For events that introduce an
object into a user's address space and for object
deletion events the audit record shall include the
name and the object security level.
4. The system administrator shall be able to
selectively audit the actions of one or more users
based on individual identity and/or object
security level.
AC-3 Extended Access Control
1. Definition of Access Control Attributes
The TCB shall define and protect access control
attributes for subjects and objects. Subject
attributes shall include named individuals or
defined groups or both. Object attributes shall
include defined access rights (e.g., read, write,
execute) that can be assigned to subject
attributes. Access control attributes
corresponding to each individual policy shall be
identified.
Sensitivity labels associated with each subject
and storage object that is directly or indirectly
accessible by subjects external to the TCB shall
be maintained by the TCB. The sensitivity labels
shall be used as the basis for mandatory access
control decisions.
The subjects and objects shall be assigned
sensitivity labels that are a combination of
hierarchical classification levels and non-
hierarchical categories, and the labels shall be
used as the basis for mandatory access control
decisions. The TCB shall be able to support two or
more such security levels.
The subject and object attributes shall accurately
reflect the sensitivity and integrity of the
subject or object. When exported by the TCB,
sensitivity labels shall accurately and
unambiguously represent the internal labels and
shall be associated with the information being
exported.
The TCB shall immediately notify a terminal user
of each change in the security level associated
with that user during an interactive session. A
terminal user shall be able to query the TCB as
desired for a display of the subject's complete
sensitivity label.
The TCB shall support the assignment of minimum
and maximum security levels to all attached
physical devices. These security levels shall be
used by the TCB to enforce constraints imposed by
the physical environments in which the devices are
located.
2. Administration of Access Control Attributes
The TCB shall define and enforce rules for
assignment and modification of access control
attributes for subjects and objects. The effect of
these rules shall be that access permission to an
object by users not already possessing access
permission is assigned only by authorized users.
These rules shall allow authorized users to
specify and control sharing of objects by named
individuals or defined groups of individuals, or
by both, and shall provide controls to limit
propagation of access rights. These controls shall
be capable of including or excluding access to the
granularity of a single user.
The rules for assignment and modification of
access control attributes shall include those for
attribute assignment to objects during import and
export operations.
Export of Labeled Information
The TCB shall designate each communication
channel and I/O device as either single-level or
multilevel. Any change in this designation shall
be done manually and shall be auditable by the
TCB. The TCB shall maintain and be able to audit
any change in the security level or levels
associated with a communication channel or I/O
device.
1. Exportation to Multilevel Devices
When the TCB exports an object to a multilevel
I/O device, the sensitivity label associated with
that object shall also be exported and shall
reside on the same physical medium as the exported
information and shall be in the same form (i.e.,
machine-readable or human-readable form). When the
TCB exports or imports an object over a multilevel
communication channel, the protocol used on that
channel shall provide for the unambiguous pairing
between the sensitivity labels and the associated
information that is sent or received.
2. Exportation to Single-Level Devices
Single-level I/O devices and single-level
communication channels are not required to
maintain the sensitivity labels of the information
they process. However, the TCB shall include a
mechanism by which the TCB and an authorized user
reliably communicate to designate the single
security level of information imported or exported
via single-level communication channels or I/O
devices.
3. Labeling Human-Readable Output
The system administrator shall be able to
specify the printable label names associated with
exported sensitivity labels. The TCB shall mark
the beginning and end of all human-readable,
paged, hardcopy output (e.g., line printer output)
with human-readable sensitivity labels that
properly represent the sensitivity of the output.
The TCB shall, by default, mark the top and bottom
of each page of human-readable, paged, hardcopy
output (e.g., line printer output) with human-
readable sensitivity labels that properly
represent the overall sensitivity of the output or
that properly represent the sensitivity of the
information on the page. The TCB shall, by default
and in an appropriate manner, mark other forms of
human-readable output (e.g., maps, graphics) with
human-readable sensitivity labels that properly
represent the sensitivity of the output. Any
override of these marking defaults shall be
auditable by the TCB.
Import of Non-labeled Data
In order to import non-labeled data, the TCB
shall request and receive from an authorized user
the security level of the data, and all such
actions shall be auditable by the TCB.
If different rules of assignment and modification
of access control attributes apply to different
subjects and/or objects, the totality of these
rules shall be shown to support the defined
policy.
3. Authorization of Subject References to Objects
The TCB shall define and enforce authorization
rules for the mediation of subject references to
objects. These rules shall be based on the access
control attributes of subjects and objects. These
rules shall, either by explicit user action or by
default, provide that objects are protected from
unauthorized access.
The scope of the authorization rules shall include
all subjects, storage objects (e.g., processes,
segments, devices) and associated access control
attributes that are directly or indirectly
accessible to subjects external to the TCB. The
scope of the authorization rules shall also
include all policy and status attributes of
subjects and storage objects (e.g., quotas, object
existence, size, access time, creation and
modification time, locked/unlocked). If different
rules apply to different subjects and objects, the
totality of these rules shall be shown to support
the defined policy.
The authorization rules for the mandatory access
control policy shall include:
The TCB shall enforce a mandatory access control
policy over all resources (i.e., subjects, storage
objects, and I/O devices that are directly or
indirectly accessible by subjects external to the
TCB. The following requirements shall hold for all
accesses between all subjects external to the TCB
and all objects directly or indirectly accessible
by these subjects: A subject can read an object
only if the hierarchical classification in the
subject's security level is greater than or equal
to the hierarchical classification in the object's
security level and the non- hierarchical
categories in the subject's security level include
all the non-hierarchical categories in the
object's security level. A subject can write an
object only if the hierarchical classification in
the subject's security level is less than or equal
to the hierarchical classification in the object's
security level and all the non-hierarchical
categories in the subject's security level are
included in the non-hierarchical categories in the
object's security level.
The authorization rules for each policy shall be
defined separately. The TCB shall define and
enforce the composition of policies, including the
enforcement of the authorization rules (e.g.,
subject and object type coverage, enforcement
precedence).
4. Subject and Object Creation and Destruction
The TCB shall control the creation and destruction
of subjects and objects. These controls shall
include object reuse. That is, all authorizations
to the information contained within a storage
object shall be revoked prior to initial
assignment, allocation or reallocation to a
subject from the TCB's pool of unused storage
objects; information, including encrypted
representations of information, produced by a
prior subjects' actions shall be unavailable to
any subject that obtains access to an object that
has been released back to the system.
CCH-2 Storage Channel Audit and Bandwidth Limitation
1. The TCB and privileged applications shall
include functions that help audit the use of
covert storage channels. These functions shall
enable the identification of the transmitter,
receiver, and specific covert channels used (e.g.,
TCB and privileged application element used to
transmit information). TCB functions that help
limit the bandwidth and/or eliminate covert
storage channels shall also be provided. The
bandwidth limits for each channel shall be
settable by system administrators.
2. The functions added to the TCB and privileged
applications for storage channel auditing shall be
identified for each channel and shall be available
in common product configurations. If audit
functions are not added to certain storage
channels (e.g., hardware storage channels),
evidence must be provided to justify why these
channels do not represent a security threat for
the intended use of the product. TCB and
privileged application functions that help limit
the bandwidth and/or eliminate covert storage
channels shall also be available in common product
configurations.
If channel bandwidth limitation and channel
elimination functions are not added to certain
storage channels (e.g., hardware storage
channels), evidence must be provided to justify
why these channels do not represent a security
threat for the intended use of the product.
SM-1 Minimal Security Management
1. The TCB shall provide an installation mechanism
for the setting and updating of its configuration
parameters, and for the initialization of its
protection-relevant data structures before any
user or administrator policy attributes are
defined. It shall allow the configuration of TCB
internal databases and tables.
2. The TCB shall provide protected mechanisms for
displaying and modifying the security policy
parameters.
3. The TCB shall provide protected mechanisms for
manually displaying, modifying, or deleting user
registration and account parameters. These
parameters shall include unique user identifiers,
their account, and their associated user name and
affiliation. The TCB shall allow the manual
enabling and disabling of user identities and/or
accounts.
4. The TCB shall support separate operator and
administrator functions. The operator functions
shall be restricted to those necessary for
performing routine operations. The operator
functions shall allow the enabling and disabling
of peripheral devices, mounting removable storage
media, backing-up and recovering user objects;
maintaining the TCB hardware and software elements
(e.g., on-site testing); and starting and shutting
down the system. [SM-3]
5. The use of the protected mechanisms for system
administration shall be limited to authorized
administrative users.
RM-3 Mediation of References to Subject and Object
Attributes
1. The TCB shall mediate all references to
subjects, objects, resources, and services (e.g.,
TCB functions) described in the TCB
specifications. The mediation shall ensure that
all references are directed to the appropriate
security-policy functions.
2. Reference mediation shall include control of
references to all subjects, objects, and resources
protected under the TCB security policy, to their
policy (i.e., access rights, security levels) and
status attributes (e.g., existence, length,
locking state).
3. References issued by privileged subjects shall
be mediated in accordance with the policy
attributes defined for those subjects.
P-2 TCB Isolation and Consistency
The TCB shall maintain a domain for its own
execution that protects it from external
interference and tampering (e.g., by reading or
modification of its code and data structures). The
protection of the TCB shall provide TCB isolation
and noncircumventability of TCB isolation
functions as follows:
1. TCB Isolation requires that (1) the address
spaces of the TCB and those of unprivileged
subjects are separated such that users, or
unprivileged subjects operating on their behalf,
cannot read or modify TCB data structures or code,
(2) the transfers between TCB and non-TCB domains
are controlled such that arbitrary entry to or
return from the TCB are not possible; and (3) the
user or application parameters passed to the TCB
by addresses are validated with respect to the TCB
address space, and those passed by value are
validated with respect to the values expected by
the TCB.
2. Non-circumventability of TCB isolation
functions requires that the permission to objects
(and/or to non-TCB data) passed as parameters to
the TCB are validated with respect to the
permissions required by the TCB, and references to
TCB objects implementing TCB isolation functions
are mediated by the TCB.
TCB protection shall also maintain the consistency
of TCB global variables and eliminate undesirable
dependencies of the TCB on unprivileged subject or
user actions.
3. Consistency of TCB global variables requires
that consistency conditions defined over TCB
internal variables, objects, and functions hold
before and after any TCB invocation.
4. Elimination of undesirable dependencies of
the TCB on unprivileged subject actions requires
that any TCB invocation by an unprivileged subject
(or user) input to a TCB call may not place the TCB
in a state such that it is unable to respond to
communication initiated by other users.
SC-1 Minimal Self Checking
Hardware and/or software features shall be
provided that can be used to periodically validate
the correct operation of the on-site hardware and
firmware elements of the TCB.
PO-2 Privilege Association with TCB Modules
1. TCB privileges needed by individual functions,
or groups of functions, of a functional component
shall be identified. Privileged TCB calls or
access to privileged TCB objects, such as user and
group registration files, password files, security
and integrity-level definition file, role
definition file, audit-log file shall also be
identified. It shall be possible to associate TCB
privileges with TCB operations performed by
administrative users.
2.The modules of a TCB function shall be
associated only with the privileges necessary to
complete their task.
3. Support for product privilege implementation
and association with TCB modules provided by
lower-level mechanisms or procedures (e.g.,
operating system, processors, language) shall be
provided.
ASSURANCES
Requirements for TCB Property Definition
PD-3 Property Specification by Model Interpretation
The developer shall provide formal models for the
functional components and sub-components of the
profile. At a minimum, a formal model of the
access control components shall be provided. The
properties of the formal models shall be clearly
stated. The developer shall provide an
interpretation of the models in the DIS of the
product's TCB. For each model entity, the
developer shall: (1) identify the TCB elements and
their DIS (if any) that implement that entity; (2)
define the operation of these TCB elements, and
(3) demonstrate, by coherent arguments, that the
DIS of these elements is consistent with the model
properties. The developer's interpretation of each
formal model, which specifies the TCB properties,
shall identify all TCB and DIS elements (if any)
that do not correspond to any model entity and
shall explain why these elements do not render the
TCB properties invalid.
An informal model of reference mediation and TCB
protection shall be provided. For the components
that are not modeled, the developer shall
interpret the functional requirements of the
protection profile within the product TCB. For
each functional requirement, the developer shall:
(1) identify the TCB elements and their TCB
interfaces (if any) that implement that
requirement; (2) describe the operation of these
TCB elements, and (3) explain why the operation of
these elements is consistent with the functional
requirement. The developer's interpretation of
each functional requirement, which describes the
TCB properties, shall include all the TCB
elements.
Requirements for TCB Element Identification
ID-2: TCB Element Justification
The vendor shall identify the TCB elements (i.e.,
software, hardware/firmware code and data
structures). Each element must be unambiguously
identified by its name, type, release, and version
number (if any).
The developer shall justify the protection
relevance of the identified elements (i.e., only
elements that can affect the correct operation of
the protection functions shall be included in the
TCB). If protection-irrelevant elements are
included in the TCB, the developer shall provide a
rationale for such inclusion.
Requirements for TCB Interface Definition
IF-2: Interface Descriptive Specification
The developer shall define all external (e.g.,
command, software, and I/O) administrative (i.e.,
privileged) and non-administrative interfaces to
the TCB.
The developer shall provide and maintain a
descriptive interface specification (DIS) of the
TCB that completely and accurately describes the
TCB in terms of exceptions, error messages, and
effects. The DIS shall identify the TCB call
conventions (e.g., parameter order, call sequence
requirements), and exceptions signaled. The DIS
shall also include the TCB call identifier,
parameter types (e.g., input, output), the effect
of the call, TCB call conventions (e.g., parameter
order, call sequence requirements), and exceptions
handled and signaled. It shall be shown to be an
accurate description of the TCB interface.
The DIS shall include those components of the TCB
that are implemented as hardware and/or firmware
if their properties are visible at the TCB
interface.
If the TCB consists of a kernel and privileged
processes, the developer shall separately identify
and define the interfaces for the kernel and each
privileged process.
The TCB interface definition must also include all
effects of a call including the direct visibility
and alterability of internal TCB variables and
functions.
Requirements for Modular Decomposition
MD-2: Module-level Decomposition
The developer shall design the TCB as a small
number (e.g., 10 to 100) of design and
implementation subsystems that have well-defined
functional relationships and shared-data
dependencies. The developer shall identify the
specific TCB protection functions (if any)
associated with each subsystem and the TCB
interfaces (if any) implemented by each subsystem.
The developer shall design each subsystem as a set
of modules. For each module, the developer shall
describe: the role or purpose of the module, the
set of related functions performed by the module,
and the module interface (i.e., the set of
invocable functions, calling conventions,
parameters, global variables, and results). The
developer shall identify the protection functions
of, and describe the interfaces between, these
modules. The developer shall choose the modules so
that the set of functions implemented by the
module, the module's contribution to the TCB
protection properties, and the interface(s) to the
module can be described concisely (e.g., the
module shall have a single purpose). The TCB
structuring into modules shall be based on well-
defined module relationships; for example, the
contains relation (e.g., A is part of B) or the
"uses" relation (e.g., A is correct only if B is
correct).
Requirements for TCB Structuring Support
SP-2: Support for Storage Objects
The TCB shall maintain process isolation. The TCB
shall separate those elements that are protection-
critical from those that are not. Features in
hardware, such as segmentation, shall be used to
support logically distinct storage objects with
separate access-control attributes (e.g.,
readable, writable).
Requirements for Implementation Support
IM-3: Module Correspondence Support
The developer shall maintain engineering diagrams
and source code (as applicable) for all TCB
elements. The diagrams and source code for each
module of the TCB shall be identified and provided
as configuration items.
Requirements for Developer Functional Testing
FT-3: Specification-Driven TCB Interface Testing
The developer shall test the TCB interface to show
that all claimed protection functions work as
stated in the TCB interface description or
specification. The tests shall exercise the
boundary conditions of the protection functions.
The developer shall generate the test conditions
and data from the Descriptive Interface
Specification(s). The developer test procedures
shall include the tests used to demonstrate the
absence of all flaws discovered in previous
versions of the TCB.
The developer shall correct all flaws discovered
by testing and shall retest the TCB to show that
all discovered flaws have been eliminated, no new
flaws have been introduced, and the protection
functions work as claimed.
Requirements for Penetration Analysis
PA-2 Flaw-Hypothesis Testing
The developer shall define the TCB configuration,
interface, and protection functions that are
subject to penetration testing. For each test, the
developer shall identify the goal of the test and
the criteria for successful penetration. The
developer shall illustrate how, in addition to
system reference manuals and TCB interface
description, the DIS, source code, and hardware
and firmware specifications are used to define
penetration-test conditions. For each test, the
developer shall document all test conditions, data
(e.g., test set-up, function call parameters, and
test outcomes), and coverage.
The developer shall generate the test conditions
from flaw-hypotheses derived by negating
assertions of TCB design capabilities and by
providing counter examples that show that these
assertions are false. The developer shall confirm
the flaw hypotheses by checking design and
implementation documentation, by defining the test
data and running test programs, or by referring to
known classes of penetration flaws found in other
TCBs. The refutation of any hypothesis shall be
documented.
For each uncovered flaw, the developer shall
define and document scenarios of flaw exploitation
and shall identify all penetration outcomes
resulting from that scenario. The cause of the
flaw shall be identified and documented.
Requirements for Covert-Channel Analysis
CCA-1 Analysis of Covert Storage Channels
1. Identification: The developer shall identify
all sources of information used in covert-storage-
channel analysis. These sources shall include TCB
reference manuals and DIS. The developer shall
define the identification method used. The
developer shall demonstrate that the chosen
identification method is sound (e.g., it leads to
the discovery of all covert storage channels in
the DIS or source documentation) and repeatable
(i.e., independent evaluators can use the method
on the same sources of covert-storage-channel
information and can obtain the same results.) The
developer shall define scenarios of use for each
covert storage channel.
2. Bandwidth Measurement or Engineering
Estimation: The developer shall define the method
used for covert-storage-channel bandwidth
estimation. In measuring TCB performance for
covert-channel-bandwidth estimation, the developer
shall satisfy the following assumptions. The
maximum bandwidth estimation shall be based on the
assumptions that the storage channel is noiseless,
that the senders and receivers are not delayed by
the presence of other processes in the product,
and that the sender-receiver synchronization time
is negligible. The choice of informal estimation
methods shall define and justify the coding method
and, therefore, the distribution of "0s" and "1s"
in all transmissions.
The developer shall select TCB primitives to be
measured for bandwidth determination from real
scenarios of covert-storage-channel use. The
developer shall specify TCB measurement
environment for the bandwidth measurements. This
specification shall include: (1) the speed of the
product functions, (2) the product configuration,
(3) the sizes of the memory and cache components,
and (4) the product initialization. The
sensitivity of the measurement results to
configuration changes shall be documented. The
covert-storage-channel measurements shall include
the fastest TCB function calls for altering,
viewing, and setting up the transmission
environment; the demonstrably fastest process
(context) switch time shall also be included in
the bandwidth measurements. All measurements shall
be repeatable.
3. Covert Channel Testing: The developer shall
test all the use of all identified covert storage
channels to determine whether the handling
functions work as intended.
Requirements for User Guidance
UG-1: Users' Guide
The developer shall provide a User Guide which
describes all protection services provided and
enforced by the TCB. The User Guide shall describe
the interaction between these services and provide
examples of their use. The User Guide may be in the
form of a summary, chapter or manual. The User
Guide shall specifically describe user
responsibilities. These shall encompass any user
responsibilities identified in the protection
profile.
Requirements for Administrative Guidance
AG-2: Detailed Administrative Guidance
The developer shall provide a Trusted Facility
Manual intended for the product administrators and
operators that describes how to use the TCB
security services (e.g., Access Control, System
Entry, or Audit) to enforce a system security
policy. The Trusted Facility Manual shall include
the procedures for securely configuring, starting,
maintaining, and halting the TCB. The Trusted
Facility Manual shall explain how to analyze audit
data generated by the TCB to identify and document
user and administrator violations of this policy.
The Trusted Facility Manual shall explain the
unique security-relevant privileges and functions
of administrators and operators. The Trusted
Facility Manual shall describe the administrative
interaction between security services.
The Trusted Facility Manual shall identify all
hardware, firmware, software, and data structures
comprising the TCB. The detailed audit record
structure for each type of audit event shall be
described. The Trusted Facility Manual shall
explain how configure the product to mitigate,
eliminate, or audit covert channel
exploitation.The Trusted Facility Manual shall
describe the cautions about and procedures for
using the TCB as a base for site-specific secure
applications. The Trusted Facility Manual shall
describe procedures for securely regenerating the
TCB after any part is changed (e.g., due to adding
devices or installing flaw corrections to the TCB
software).
The Trusted Facility Manual shall be distinct from
User Guidance, and encompass any administrative
responsibilities identified in security
management.
Requirements for Trusted Generation
TG-2: Trusted Generation With Fail-Safe Defaults
The developer shall establish and document the
procedures that a consumer must perform to
generate an operational TCB from the delivered
copy of the master TCB. The consumer documentation
shall identify any system parameters, which are
initialized or set during system generation, that
affect the TCB's conformance to the protection
profile and state the acceptable ranges of values
for those parameters. The product shall be
delivered with each of these parameters set to its
fail-safe defaults.
Requirements for Life Cycle Process
LC-2: Standardized Life Cycle Process
The developer shall develop and maintain the
product using a well defined, standardized
engineering process. The developer shall explain
why the process was chosen and how the developer
uses it to develop and maintain the product. The
process shall incorporate a security policy that
states the technical, physical, procedural,
personnel, and other measures used by the
developer to protect the product and its
documentation. The developer shall demonstrate
that each development process and support process
requirement of the protection profile is satisfied
by some part, or parts, of the developer's
process. The developer shall identify the
programming languages used to develop the TCB
software and reference the definitions of those
languages. The developer shall identify any
implementation dependent options of the
programming language compiler(s) used to implement
the TCB software.
Requirements for Configuration Management
CM-2: Automated Source Code Control
The developer shall establish configuration
control and generation procedures for developing
and maintaining the TCB. The procedures shall be
employed to ensure that changes to the TCB are
consistent with the product's protection
properties and security policy. The developer
shall employ these procedures to track changes to
development evidence, implementation data (e.g.,
source code and hardware diagrams), executable
versions of the TCB, test documentation and
procedures, identified flaws, and consumer
documentation. The procedures shall include
automated tools to control the software source
code that comprises the TCB.
The configuration control procedures shall assure
a consistent mapping among documentation and code
associated with the current version of the TCB and
permit the regeneration of any supported version
of the TCB.
Requirements for Evidence of TCB Protection Properties
EPP-3 Evidence of Formal Model Interpretation in the DIS
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. This documentation shall
describe how the TCB implements the reference
monitor concept. The developer shall also provide
a formal access-control model and an informal
reference mediation and TCB protection model. The
TCB properties, which are defined by this
correspondence and the interpretation of these
models within the DIS of the TCB shall be
documented by the product developer.
Requirements for Evidence of Product Development
EPD-3: Analysis Of The TCB External Interface
The developer shall provide TCB Design
Specifications that include: a list of the TCB
elements (hardware, software, and firmware
configuration items); a list of protection
services provided to the TCB by hardware,
software, and firmware that is not part of the
TCB; an explanation of the techniques and criteria
used during the modular decomposition of the TCB;
a description of the policy allocations,
functions, and interactions among the major TCB
subsystems; and module level descriptions of all
software and hardware in the TCB.
The developer shall provide a Descriptive
Interface Specification (DIS) that describes the
functions, effects, exceptions and error messages
visible at the TCB interface. The developer shall
show that the DIS is an accurate representation of
the TCB's external interfaces.
The developer shall provide TCB Implementation
Data consisting of the engineering diagrams for
all hardware included in the TCB and the source
code used to generate the TCB software and
firmware.
Requirements for Evidence of Functional Testing
EFT-3: Evidence of Specification-Driven Testing
The developer shall provide evidence of the
functional testing that includes the test plan,
the test procedures, and the results of the
functional testing. The test, plans, procedures,
and results shall be maintained under the same
configuration control as the TCB software. The
test plans shall identify the TCB specification
used in the derivation of the test conditions,
data, and coverage analysis.
Requirements for Evidence of Penetration Analysis
EPA-2: Evidence of Flaw-Hypothesis Generation and Testing
The developer shall provide evidence of
penetration testing. The penetration evidence
shall identify all product documentation and
development evidence on which the search for flaws
was based. The penetration evidence shall describe
the scenarios for exploiting each potential flaw
in the system and the penetration test conditions,
data (e.g., test set-up, function call parameters,
and test outcomes), coverage, and conclusions
derived from each scenario. The penetration
evidence shall summarize both refuted and
confirmed flaws hypothesis.
Requirements for Evidence of Covert Channel Analysis
ECC-1: Evidence of Covert Storage Channel Analysis and
Handling
The developer's documentation shall present the
results of the covert-storage-channel analysis and
the trade-offs involved in restricting these
channels. All auditable events that may be used in
the exploitation of known covert storage channels
shall be identified. The developer shall provide
the bandwidths of known covert-storage-channels
whose use is not detectable by the auditing
mechanism. The documentation of each identified
storage channel shall consist of the variable that
can be viewed/altered by the channel and the TCB
interface functions that can alter or view that
variable. The measurements of each TCB function
call used by covert-storage channels must be
documented and the bandwidth computation shall be
included for each channel. The measurement
environment should be documented as specified.
Test documentation shall include results of
testing the effectiveness of the methods used to
reduce covert-storage-channel bandwidths.
Requirements for Evidence of Product Support
EPS-2: Evidence of Defined Product Support
The developer shall provide documentation that
defines the policies, procedures, plans, and tools
established by the developer to satisfy the
Operational Support and Development Environment
requirements of the protection profile.
Requirements for Test Analysis
TA-4: Comprehensive Test Analysis
The evaluator shall assess whether the producer
has performed the activities defined in the
development assurance requirements of the
protection profile for functional testing and
penetration analysis, and whether the producer has
documented these activities as defined in the
development evidence requirements of the
protection profile. The evaluator shall analyze
the results of the producer's testing activities
for completeness of coverage and consistency of
results, and general correctness (e.g., defect
trend from regression testing). This analysis
shall examine the testability of requirements, the
adequacy of the tests to measure the required
properties, the deviation of the actual results
obtained from the expected results. The analysis
shall extend to trace all defects identified,
corrected, and retested. The analysis shall
include an assessment of test coverage and
completeness, and defect frequency. The results of
testing shall be interpreted in terms that express
product performance and protection adequacy. The
evaluator shall determine whether the product's
protection properties, as defined for all
protection-relevant modules of the TCB, and all
relevant known penetration flaws have been tested.
The evaluator shall independently develop, test,
and document additional flaw hypotheses. The
evaluator shall assess testing results to
determine whether the product's TCB works as
claimed, that the TCB's implementation is
consistent with the DIS, and whether there are any
obvious ways (i.e., ways that are known, or that
are readily apparent or easily discovered in
product documentation) for an unauthorized user to
bypass the policy implemented by the TCB or
otherwise defeat the product's TCB, and whether
all discovered TCB flaws have been corrected and
no new TCB flaws introduced. No design flaws and
no more than a few correctable implementation
flaws may be found during testing and there shall
be reasonable confidence that few remain. The
testing results shall show that the methods used
to reduce covert channel bandwidths have been
effective for all evaluated configurations. The
evaluator shall determine whether the product is
relatively resistant to penetrations.
Requirements for Independent Testing
IT-3: Comprehensive Independent Testing.
The evaluator shall independently perform
functional and elementary penetration testing to
confirm test results. This testing may be
selective and shall be based on (1) the results of
other independent and/or producer testing, (2) the
TCB's DIS, (3) other product design and
implementation documentation, (4) the product's
user and administrative documentation, (5)
relevant known penetration flaws, and (6)
evaluator-developed TCB penetration flaw
hypotheses and corresponding tests that attempt to
exploit the hypothesized flaws. Satisfactory
completion consists of demonstrating that all TCB
functions work as described in the product's
relevant documentation, that test results are
consistent, and that no discrepancies exist
between the documentation and the product.
Satisfactory penetration test completion shall be
determined by the subjective judgement (which may
be supported algorithmically) of the evaluator.
Test duration agreements may further constrain
this judgement. Categorization of an actual
penetration flaw shall be based on the
reproducibility of that flaw. Flaws that are
discovered, but are not reproducible shall remain
categorized as potential penetration flaws. All
actual penetration flaws must be corrected and
retested.
The evaluator shall provide a penetration test
plan document that describes the additional
evaluator-developed flaw hypotheses and associated
tests. The evaluator shall execute these tests and
shall report any discovered flaws to the producer
as part of the testing results. At the conclusion
of penetration testing, the evaluator shall
provide copies of this penetration test plan and
its test results to the producer. The producer
shall ensure that this test plan and its test
results are incorporated into the rest of the
product's testing documentation and that such
documentation is available for further analysis
throughout the life of the product.
The evaluator shall test for covert channel
bandwidth reductions to determine the
effectiveness of handling method(s) in reducing
the bandwidths of identified covert channels for
all evaluated configurations.
If the independent testing is performed at beta-
test sites, the producer shall supply the beta-
test plan and the test results. The evaluator
shall review the scope and depth of beta testing
with respect to the required protection
functionality, and shall verify independence of
both the test sites and the producer's and beta-
test user's test results. The evaluator shall also
confirm that the test environment of the beta-test
site(s) adequately represents the environment
specified in the protection profile.
Requirements for Development Environment
DER-2: Enhanced Development Environment Review
The evaluator shall review the producer's
development and maintenance process description
documentation and shall conduct a random audit of
the producer's processes using the evidence
generated by each process to determine the degree
of discipline enforced upon and within the
process, and to determine the protection
characteristics associated with the product's
development and maintenance. The results of this
review shall establish, for the evaluator, the
producer's development environment, its policies,
and the degree of enforcement maintained during
development execution. The results of this review
shall also confirm the producer's general
conformance with relevant development environment
requirements.
Requirements for Operational Support
OSR-2 Enhanced Operational Support Review
The evaluator shall review all documentation
focused on the activities of product use (e.g.,
Users Manuals) and product administration
including installation, operation, maintenance,
and trusted recovery (e.g., Trusted Facility
Management Manuals). This review shall assess the
clarity of presentation, difficulty in locating
topics of interest, ease of understanding, and
completeness of coverage. The need for separate
manuals dedicated to protection-relevant aspects
of the product should be assessed for
effectiveness. The evaluator shall randomly select
a sample of the documented protection-relevant
features and procedures and execute them to
determine if their descriptions are accurate and
correct.
Requirements for Design Analysis
DA-2: Enhanced Design Analysis
The evaluator shall determine whether the producer has
performed the activities defined in the development process
assurance requirements of the protection profile for TCB
property definition and TCB design. The evaluator shall
determine whether the producer has documented these
activities as defined in the development evidence
requirements of the protection profile. The evaluator shall
analyze the results of the producer's activities for
completeness, consistency, and correctness of design with
respect to requirements.
Requirements for Implementation Analysis
CI-1: Elementary Implementation Analysis
The evaluator shall conduct a code inspection on a
small sample of randomly selected product code.
The assessment shall focus on clarity of the
coding style, adherence to coding standards,
coding documentation, and on possible software
defects that may be present with respect to the
product's informal design. The inspection shall be
performed to obtain only a sample of possible
software defects, not to capture all such possible
defects. The evaluator shall report all discovered
defects to the producer; the assessment shall
report the number of defects found per line of
code inspected from the random sample size. Use of
producer-provided code inspection results can
supplement this sample inspection. All trapdoors
built into the product for maintenance purposes
shall be identified by the producer and shown to
be protected by the product.
DRAFT
LABEL BASED PROTECTION
FOR
MULTI-USER INFORMATION SYSTEMS
LEVEL 3
(LP-3)
A Protection Profile
Derived from the Federal Criteria for IT Security
Version 1.0
December 1992
This document is undergoing review and
is subject to modification or withdrawal.
The contents of this document should not
be referenced in other publications.
Supersedes the
Trusted Computer System Evaluation Criteria
Class B3
DRAFT
LABEL-BASED PROTECTION - 3 (LP-3)
This Protection Profile has been developed to define a set
of technical measures that can be incorporated into remote-
access, resource- and information-sharing Information
Technology (IT) products that will be used to protect up to
three levels and multiple categories of National Security
Information classified according to US Executive Order 12356
(EO 12356). This profile can also be used to protect any
information that has been designated as sensitive information
for which information separation and access are based on
sensitivity markings applied to the information. This profile
is intended for use in environments where the presence
potentially malicious application software (e.g., Trojan
Horses) mandate the use of high-assurance products.
Compliant IT products will provide highly-structured,
conceptually simple protection mechanisms for a multi-level
information processing environment with which an organization
can construct an automated information system to enhance or
optimize the organization's ability to perform its mission.
In LP-3 conformant systems, the TCB is demonstrably based
on a clearly defined and documented formal security policy
model (i.e., the interpretation of the policy model within the
TCB is shown to be valid). The TCB is resistant to
penetration. In relation to lower levels of protection
functionality, LP-3 conformat systems have the following
additional features.
a. The TCB must satisfy all requirements of the reference
monitor concept (i.e., TCB protection, reference
mediation, and TCB structuring and complexity
minimization to enhance TCB verification; viz.,
Appendix B).
b. Covert storage and timing channels are analyzed and
handled.
c. The TCB includes trusted recovery functions and a
trusted path mechanism that includes general user
commands, not just login commands.
d. The audit mechanisms include alarms that signal
accumulation of events representing potential
security violations.
e. Security management is enhanced by the fine-grain
separation of system administrator and operator
functions and by the minimization of security
irrelevant functions of security roles.
f. Stringent configuration management controls are
imposed.
g. The TCB must be found resistant to penetration.
Cross References:
o Existing Criteria:
(1) TCSEC: B3
(2) ITSEC
(3) CTCPEC
o Other Protection Profiles
(1) TBD
COMPONENT SUMMARY:
LP-3 Functional Component Summary
.--------------------------------------------.
| | Code & |
| Functional Component | Level |
|============================================|
| Security Policy Support |
|----------------------------------+---------|
| Accountability | |
|----------------------------------+---------|
| Identification uthentication | I&A-2 |
|----------------------------------+---------|
| System Entry | ---- |
|----------------------------------+---------|
| Trusted Path | TP-2 |
|----------------------------------+---------|
| Audit | AD-1+ |
|----------------------------------+---------|
| Access Control | AC-3+ |
|----------------------------------+---------|
| Discretionary | AC-3+ |
|----------------------------------+---------|
| Non-Discretionary | AC-3 |
|----------------------------------+---------|
| Covert Channel Handling | CCH-3 |
|----------------------------------+---------|
| Availability | ---- |
|----------------------------------+---------|
| Resource Allocation | ---- |
|----------------------------------+---------|
| Fault Tolerance | ---- |
|----------------------------------+---------|
| Security Mgmt. | SM-1++ |
|----------------------------------+---------|
| Reference Mediation | RM-3 |
|----------------------------------+---------|
| TCB Logical Protection | P-3 |
|----------------------------------+---------|
| TCB Physical Protection | ---- |
|----------------------------------+---------|
| TCB Self-checking | SC-1 |
|----------------------------------+---------|
| TCB Start-Up and Recovery | TR-1 |
|----------------------------------+---------|
| TCB Privileged Operation | PO-2 |
|----------------------------------+---------|
| TCB Ease-of-Use | ---- |
`--------------------------------------------'
LP-3 Assurance Component Summary
.---------------------------------------.
| Assurance Components | T6 |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-3 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-2 |
|--------------------------------+------|
| TCB Modular Decomposition | MD-3 |
|--------------------------------+------|
| TCB Structuring Support | SP-3 |
|--------------------------------+------|
| TCB Design Disciplines | DD-2 |
|--------------------------------+------|
| TCB Implementation Support | IM-3 |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-3 |
|--------------------------------+------|
| Penetration Analysis | PA-2 |
|--------------------------------+------|
| Covert Channel Analysis | CCA2 |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-3 |
|--------------------------------+------|
| Trusted Generation | TG-3 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | LC-3 |
|--------------------------------+------|
| Configuration Management | CM-3 |
|--------------------------------+------|
| Trusted Distribution | ---- |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP3 |
|--------------------------------+------|
| Product Development | EPD4 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT3 |
|--------------------------------+------|
| Penetration Analysis | EPA2 |
|--------------------------------+------|
| Covert Channel Analysis | ECC2 |
|--------------------------------+------|
| Product Support | EPS3 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-4 |
|--------------------------------+------|
| Independent Testing | IT-3 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | DER3 |
|--------------------------------+------|
| Operational Support | OSR3 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | DA-3 |
|--------------------------------+------|
| Implementation | CI-3 |
`---------------------------------------'
RATIONALE
11. Information Protection Policy
It is anticipated that organizations wishing to process two
to three levels of classified information with multiple
categories will want to use IT products that are compliant
with this profile in their automated information processing
systems. These organizations should be able to trust the
profile-compliant IT product to contribute to the protection
of the classified information at least as much as they trust
the properly cleared personnel who are using and managing the
system.
12. Protection Philosophy
This profile presumes a hostile environment with divided,
aggressive users. It provides control of access to shared
resources both (1) on the basis of attributes that are
controlled by the ordinary users of the system and (2) on the
basis of attributes that are controlled only by the system
administrators.
Profile compliant IT products will minimally meet the
following objectives:
a. Employ a reference validation mechanism to enforce a
formally defined security policy that describes the
rules for controlling access to system subjects and
objects and use the access control rules to enforce an
information flow policy that aims to control the use
of covert storage and timing channels.
b. Associate explicit sensitivity labels with each
subject and object in the system and each port through
which information may be exported from or imported to
the system. Maintain the accuracy of the sensitivity
labels as information moves within the system and
through the ports.
c. Authenticate the claimed identity of each external
human user of the IT product prior to establishing any
internal entity to act on behalf of that user and
firmly bind the authenticated user identity to the
internal entity.
d. Selectively keep and protect a log of all actions or
events (including use of covert storage channels) that
could affect system security so that they can be
accurately attributed to the known user or system
entity responsible for causing the action or event.
Also, alert the system administrator when a series of
events indicates an imminent violation of the security
policy.
e. Contains hardware and software mechanisms that can be
independently evaluated to provide sufficient
assurance that the system satisfies the previous four
objectives.
f. Implements the enforcement of objectives a through d
in such a fashion that the enforcing mechanisms are
protected from tampering and unauthorized changes by
the information moving entities that the mechanisms
are supposed to control.
13. Expected Threats
The requirements for profile conforming IT products assume
that these products are being used in an environment where
there are different levels and categories of classified data
and users of differing clearance levels. A conforming IT
product can be reasonably expected to protect the
confidentiality of information in an environment where there
are three levels and multiple categories of classified data,
and two or more levels of cleared users and where there are
collaborating, malicious users and software at each clearance
level.
14. Assumed Environment
14.1 Characteristics
IT products complying with the requirements set forth in
this profile are expected to be used in an environment with
the following characteristics:
a. Multiple users will be accessing the operating system
at the same time.
b. The IT product hardware base (e.g., CPU, printers,
terminals, etc.) is protected from unauthorized
physical access.
c. One or more personnel are assigned to manage the
system in which the IT product is incorporated,
including the security of the information it contains.
d. A need to control user access to information exists
and is based on an explicit sensitivity marking
associated with the information (e.g, Secret or Top
Secret).
e. There is a need to control user access to information
exists and is based on that user's identity and
membership in organizations or groups.
f. The IT product provides facilities for some or all of
the authorized users to create programs that use the
applications programming interface (API) and make
those programs available to other users.
g. The IT product is used to provide a cooperative
environment for the users to accomplish some task or
group of tasks.
14.2 Environment Dependencies
Secure installation and operation of a product satisfying
these profile requirements depends on provision of a number
of elements in the installation environment. These include:
a. Physical security must be provided. For US Government
classified operation, physical security equivalent to
PP-2 would be required.
b. Cabling to other devices must be shown to be
consistent with policy implemented by the product. For
example, a "port" in the product is required to have
an assigned label. No device can be connected to the
port unless it has been established externally that
the device is allowed to receive data with the same
label.
c. Personnel allowed to access data processed by the
installed product must already be authorized for such
access.
15. Intended Use
Conforming IT products are useful in both general-purpose
office automation environments with multiple data
sensitivities (or "classifications") and multiple levels of
user authorizations (or "clearances") and in specialized
computing, network and mission environments. Examples of the
office automation environment might include military
headquarters and highly competitive procurement offices.
Examples of the network environments include use as the basis
for a multilevel secure network management center or a trusted
guard gateway operating between two networks processing
different levels of information. An example of the specialized
mission environment might be as a platform for a portable
battlefield map and mission management application.
FUNCTIONAL REQUIREMENTS
Requirements for Identification and Authentication
I&A-2 Identification, Authentication, and Authorization
1. The TCB shall require users to identify
themselves to it before beginning to perform any
other actions that the TCB is expected to mediate.
The TCB shall be able to enforce individual
accountability by providing the capability to
uniquely identify each individual user. The TCB
shall also provide the capability of associating
this identity with all auditable actions taken by
that individual.
2. The TCB shall maintain authentication data that
includes information for verifying the identity of
individual users (e.g., passwords) as well as
information for determining the clearance and
authorization of individual users. These data
shall be used by the TCB to authenticate the
user's identity and to ensure that the subject
security level and authorizations of subjects
external to the TCB that may be created to act on
behalf of the individual user are dominated by the
clearance and authorization of that user).
3. The TCB shall protect authentication data so
that it cannot be used by any unauthorized user.
Requirements for Trusted Path
TP-2 Trusted User-to-TCB Communication
The TCB shall support a trusted communication path
between itself and users for use whenever a
positive user-to-TCB connection is required (e.g.,
login, change of policy attributes).
Communications via this trusted path shall be
activated exclusively by a user or the TCB and
shall be logically isolated and unmistakably
distinguishable from other communication paths.
Requirements for Audit
AD-1+ Minimal Audit
1. The TCB shall be able to create, maintain, and
protect from modification or unauthorized access
or destruction an audit trail of accesses to the
objects it protects. The audit data shall be
protected by the TCB so that read access to it is
limited to those who are authorized for audit
data.
2. The TCB shall be able to record the following
types of events:
- use of the identification and authentication
mechanisms;
- introduction of objects into a user's address
space (e.g., file open, program initiation), and
deletion of objects;
- actions taken by computer operators and system
administrators and/or system security officers.
The TCB shall be able to record any override of
human-readable output markings. The TCB shall also
be able to audit the identified event that may be
used in the exploitation of covert channels.
The TCB shall contain a mechanism that is able to
monitor the occurrence or accumulation of
auditable events that may indicate an imminent
violation of the product's security policy. This
mechanism shall be able to immediately notify the
security administrator when thresholds are
exceeded, and, if the occurrence or accumulation
of these security relevant events continues, the
system shall take the least disruptive action to
terminate the event. [AD-3]
3. For each recorded event, the audit record shall
identify: date and time of the event, user, type
of event, and success or failure of the event. For
identification/authentication events the origin of
request (e.g., terminal ID) shall be included in
the audit record. For events that introduce an
object into a user's address space and for object
deletion events the audit record shall include the
name and the object security level.
4. The system administrator shall be able to
selectively audit the actions of one or more users
based on individual identity and/or object
security level.
Requirements for Access Control
AC-3 + Extended Access Control
1. Definition of Access Control Attributes
The TCB shall define and protect access control
attributes for subjects and objects. Subject
attributes shall include named individuals or
defined groups or both. Object attributes shall
include defined access rights (e.g., read, write,
execute) that can be assigned to subject
attributes. Access control attributes
corresponding to each individual policy shall be
identified.
Sensitivity labels associated with each subject
and storage object that is directly or indirectly
accessible by subjects external to the TCB shall
be maintained by the TCB. The sensitivity labels
shall be used as the basis for mandatory access
control decisions.
The subjects and objects shall be assigned
sensitivity labels that are a combination of
hierarchical classification levels and non-
hierarchical categories, and the labels shall be
used as the basis for mandatory access control
decisions. The TCB shall be able to support two or
more such security levels.
The subject and object attributes shall accurately
reflect the sensitivity and integrity of the
subject or object. When exported by the TCB,
sensitivity labels shall accurately and
unambiguously represent the internal labels and
shall be associated with the information being
exported.
The TCB shall immediately notify a terminal user
of each change in the security level associated
with that user during an interactive session. A
terminal user shall be able to query the TCB as
desired for a display of the subject's complete
sensitivity label.
The TCB shall support the assignment of minimum
and maximum security levels to all attached
physical devices. These security levels shall be
used by the TCB to enforce constraints imposed by
the physical environments in which the devices are
located.
2. Administration of Access Control Attributes
The TCB shall define and enforce rules for
assignment and modification of access control
attributes for subjects and objects. The effect of
these rules shall be that access permission to an
object by users not already possessing access
permission is assigned only by authorized users.
These rules shall allow authorized users to
specify and control sharing of objects by named
individuals or defined groups of individuals, or
by both, and shall provide controls to limit
propagation of access rights. (i.e., these rules
shall define the distribution, revocation, and
review of access control attributes). The controls
defined by these rules shall be capable of
specifying for each named object, a list of
individuals and a list of groups of named
individuals, with their respective access rights
to that object. Furthermore, for each named
object, it shall be possible to specify a list of
named individuals and a list of groups of named
individuals for which no access to the object is
given [AC-4}. These controls shall be capable of
including or excluding access to the granularity
of a single user.
The rules for assignment and modification of
access control attributes shall include those for
attribute assignment to objects during import and
export operations.
Export of Labeled Information
The TCB shall designate each communication
channel and I/O device as either single-level or
multilevel. Any change in this designation shall
be done manually and shall be auditable by the
TCB. The TCB shall maintain and be able to audit
any change in the security level or levels
associated with a communication channel or I/O
device.
1. Exportation to Multilevel Devices
When the TCB exports an object to a multilevel
I/O device, the sensitivity label associated with
that object shall also be exported and shall
reside on the same physical medium as the exported
information and shall be in the same form (i.e.,
machine-readable or human-readable form). When the
TCB exports or imports an object over a multilevel
communication channel, the protocol used on that
channel shall provide for the unambiguous pairing
between the sensitivity labels and the associated
information that is sent or received.
2. Exportation to Single-Level Devices
Single-level I/O devices and single-level
communication channels are not required to
maintain the sensitivity labels of the information
they process. However, the TCB shall include a
mechanism by which the TCB and an authorized user
reliably communicate to designate the single
security level of information imported or exported
via single-level communication channels or I/O
devices.
3. Labeling Human-Readable Output
The system administrator shall be able to
specify the printable label names associated with
exported sensitivity labels. The TCB shall mark
the beginning and end of all human-readable,
paged, hardcopy output (e.g., line printer output)
with human-readable sensitivity labels that
properly represent the sensitivity of the output.
The TCB shall, by default, mark the top and bottom
of each page of human-readable, paged, hardcopy
output (e.g., line printer output) with human-
readable sensitivity labels that properly
represent the overall sensitivity of the output or
that properly represent the sensitivity of the
information on the page. The TCB shall, by default
and in an appropriate manner, mark other forms of
human-readable output (e.g., maps, graphics) with
human-readable sensitivity labels that properly
represent the sensitivity of the output. Any
override of these marking defaults shall be
auditable by the TCB.
Import of Non-labeled Data
In order to import non-labeled data, the TCB
shall request and receive from an authorized user
the security level of the data, and all such
actions shall be auditable by the TCB.
If different rules of assignment and modification
of access control attributes apply to different
subjects and/or objects, the totality of these
rules shall be shown to support the defined
policy.
3. Authorization of Subject References to Objects
The TCB shall define and enforce authorization
rules for the mediation of subject references to
objects. These rules shall be based on the access
control attributes of subjects and objects. These
rules shall, either by explicit user action or by
default, provide that objects are protected from
unauthorized access.
The scope of the authorization rules shall include
all subjects, storage objects (e.g., processes,
segments, devices) and associated access control
attributes that are directly or indirectly
accessible to subjects external to the TCB. The
scope of the authorization rules shall also
include all policy and status attributes of
subjects and storage objects (e.g., quotas, object
existence, size, access time, creation and
modification time, locked/unlocked). If different
rules apply to different subjects and objects, the
totality of these rules shall be shown to support
the defined policy.
The authorization rules for the mandatory access
control policy shall include:
The TCB shall enforce a mandatory access control
policy over all resources (i.e., subjects, storage
objects, and I/O devices that are directly or
indirectly accessible by subjects external to the
TCB. The following requirements shall hold for all
accesses between all subjects external to the TCB
and all objects directly or indirectly accessible
by these subjects: A subject can read an object
only if the hierarchical classification in the
subject's security level is greater than or equal
to the hierarchical classification in the object's
security level and the non- hierarchical
categories in the subject's security level include
all the non-hierarchical categories in the
object's security level. A subject can write an
object only if the hierarchical classification in
the subject's security level is less than or equal
to the hierarchical classification in the object's
security level and all the non-hierarchical
categories in the subject's security level are
included in the non-hierarchical categories in the
object's security level.
The authorization rules for each policy shall be
defined separately. The TCB shall define and
enforce the composition of policies, including the
enforcement of the authorization rules (e.g.,
subject and object type coverage, enforcement
precedence).
4. Subject and Object Creation and Destruction
The TCB shall control the creation and destruction
of subjects and objects. These controls shall
include object reuse. That is, all authorizations
to the information contained within a storage
object shall be revoked prior to initial
assignment, allocation or reallocation to a
subject from the TCB's pool of unused storage
objects; information, including encrypted
representations of information, produced by a
prior subjects' actions shall be unavailable to
any subject that obtains access to an object that
has been released back to the system.
Requirements for Covert Channel Handling
CCH-3 Timing Channel Audit and Bandwidth Limitation
1. The TCB and privileged applications shall
include functions that help audit the use of
covert storage channels. These functions shall
enable the identification of the transmitter,
receiver, and specific covert channels used (e.g.,
TCB and privileged application element used to
transmit information). TCB functions that help
limit the bandwidth and/or eliminate covert
storage channels shall also be provided. The
bandwidth limits for each channel shall be
settable by system administrators.
2. The functions added to the TCB and privileged
applications for storage channel auditing shall be
identified for each channel and shall be available
in common product configurations. If audit
functions are not added to certain storage
channels (e.g., hardware storage channels),
evidence must be provided to justify why these
channels do not represent a security threat for
the intended use of the product. TCB and
privileged application functions that help limit
the bandwidth and/or eliminate covert storage or
timing channels shall also be available in common
product configurations.
If channel bandwidth limitation and channel
elimination functions are not added to certain
storage or timing channels (e.g., hardware
channels), evidence must be provided to justify
why these channels do not represent a security
threat for the intended use of the product.
Requirements for Security Management
SM-1++ Minimal Security Management
1. The TCB shall provide an installation mechanism
for the setting and updating of its configuration
parameters, and for the initialization of its
protection-relevant data structures before any
user or administrator policy attributes are
defined. It shall allow the configuration of TCB
internal databases and tables.
2. The TCB shall provide protected mechanisms for
displaying and modifying the security policy
parameters.
3. The TCB shall provide protected mechanisms for
manually displaying, modifying, or deleting user
registration and account parameters. These
parameters shall include unique user identifiers,
their account, and their associated user name and
affiliation. The TCB shall allow the manual
enabling and disabling of user identities and/or
accounts.
4. The TCB shall support separate operator and
administrator functions. The operator functions
shall be restricted to those necessary for
performing routine operations. The operator
functions shall allow the enabling and disabling
of peripheral devices, mounting of removable
storage media, backing-up and recovering user
objects; maintaining the TCB hardware and software
elements (e.g., on-site testing); and starting and
shutting down the system. The administrative
functions shall support separate security
administrator and auditor roles. The TCB shall
enable the administrators to perform their
functions only after taking distinct auditable
action to assume an administrator role. Non-
security functions that can be performed in the
security administrative role shall be limited
strictly to those essential to performing the
security role effectively.[SM-4]
5. The use of the protected mechanisms for system
administration shall be limited to authorized
administrative users.
Requirements for Reference Mediation
RM-3 Mediation of References to Subject and Object
Attributes
1. The TCB shall mediate all references to
subjects, objects, resources, and services (e.g.,
TCB functions) described in the TCB
specifications. The mediation shall ensure that
all references are directed to the appropriate
security-policy functions.
2. Reference mediation shall include control of
references to all subjects, objects, and resources
protected under the TCB security policy, to their
policy (i.e., access rights, security levels) and
status attributes (e.g., existence, length,
locking state).
3. References issued by privileged subjects shall
be mediated in accordance with the policy
attributes defined for those subjects.
Requirements for Logical TCB Protection
P-3 TCB Isolation and Timing Consistency
The TCB shall maintain a domain for its own
execution that protects it from external
interference and tampering (e.g., by reading or
modification of its code and data structures). The
protection of the TCB shall provide TCB isolation
and noncircumventability of TCB isolation
functions as follows:
1. TCB Isolation requires that (1) the address
spaces of the TCB and those of unprivileged
subjects are separated such that users, or
unprivileged subjects operating on their behalf,
cannot read or modify TCB data structures or code,
(2) the transfers between TCB and non-TCB domains
are controlled such that arbitrary entry to or
return from the TCB are not possible; and (3) the
user or application parameters passed to the TCB
by addresses are validated with respect to the TCB
address space, and those passed by value are
validated with respect to the values expected by
the TCB.
2. Non-circumventability of TCB isolation
functions requires that the permission to objects
(and/or to non-TCB data) passed as parameters to
the TCB are validated with respect to the
permissions required by the TCB, and references to
TCB objects implementing TCB isolation functions
are mediated by the TCB.
TCB protection shall also maintain the consistency
of TCB global variables and eliminate undesirable
dependencies of the TCB on unprivileged subject or
user actions.
3. Consistency of TCB global variables requires
that consistency conditions defined over TCB
internal variables, objects, and functions hold
before and after any TCB invocation.
4. Elimination of undesirable dependencies of
the TCB on unprivileged subject actions requires
that any TCB invocation by an unprivileged subject
(or user) input to a TCB call may not place the TCB
in a state such that it is unable to respond to
communication initiated by other users.
Furthermore, TCB protection shall maintain the
timing consistency of condition checks.
5. Timing consistency of condition checks
requires that a validation check holds at the
instant when the TCB action depending on that
check is performed.
Requirements for TCB Self Checking
SC-1 Minimal Self Checking
Hardware and/or software features shall be
provided that can be used to periodically validate
the correct operation of the on-site hardware and
firmware elements of the TCB.
Requirements for TCB Start-Up and Recovery
TR-1 Minimal Requirements for Recovery or Start-up
Procedures and/or mechanisms shall be provided to
assure that, after a TCB failure or other
discontinuity, recovery without protection
compromise is obtained.
Requirements for TCB Privileged Operation
PO-2 Privilege Association with TCB Modules
1. TCB privileges needed by individual functions,
or groups of functions, of a functional component
shall be identified. Privileged TCB calls or
access to privileged TCB objects, such as user and
group registration files, password files, security
and integrity-level definition file, role
definition file, audit-log file shall also be
identified. It shall be possible to associate TCB
privileges with TCB operations performed by
administrative users.
2.The modules of a TCB function shall be
associated only with the privileges necessary to
complete their task.
3. Support for product privilege implementation
and association with TCB modules provided by
lower-level mechanisms or procedures (e.g.,
operating system, processors, language) shall be
provided.
ASSURANCES
Requirements for TCB Property Definition
PD-3 Property Specification by Model Interpretation
The developer shall provide formal models for the
functional components and sub-components of the
profile. At a minimum, a formal model of the
access control components shall be provided. The
properties of the formal models shall be clearly
stated. The developer shall provide an
interpretation of the models in the DIS of the
product's TCB. For each model entity, the
developer shall: (1) identify the TCB elements and
their DIS (if any) that implement that entity; (2)
define the operation of these TCB elements, and
(3) demonstrate, by coherent arguments, that the
DIS of these elements is consistent with the model
properties. The developer's interpretation of each
formal model, which specifies the TCB properties,
shall identify all TCB and DIS elements (if any)
that do not correspond to any model entity and
shall explain why these elements do not render the
TCB properties invalid.
An informal model of reference mediation and TCB
protection shall be provided. For the components
that are not modeled, the developer shall
interpret the functional requirements of the
protection profile within the product TCB. For
each functional requirement, the developer shall:
(1) identify the TCB elements and their TCB
interfaces (if any) that implement that
requirement; (2) describe the operation of these
TCB elements, and (3) explain why the operation of
these elements is consistent with the functional
requirement. The developer's interpretation of
each functional requirement, which describes the
TCB properties, shall include all the TCB
elements.
Requirements for TCB Element Identification
ID-2: TCB Element Justification
The vendor shall identify the TCB elements (i.e.,
software, hardware/firmware code and data
structures). Each element must be unambiguously
identified by its name, type, release, and version
number (if any).
The developer shall justify the protection
relevance of the identified elements (i.e., only
elements that can affect the correct operation of
the protection functions shall be included in the
TCB). If protection-irrelevant elements are
included in the TCB, the developer shall provide a
rationale for such inclusion.
Requirements for TCB Interface Definition
IF-2: Interface Descriptive Specification
The developer shall define all external (e.g.,
command, software, and I/O) administrative (i.e.,
privileged) and non-administrative interfaces to
the TCB.
The developer shall provide and maintain a
descriptive interface specification (DIS) of the
TCB that completely and accurately describes the
TCB in terms of exceptions, error messages, and
effects. The DIS shall identify the TCB call
conventions (e.g., parameter order, call sequence
requirements), and exceptions signaled. The DIS
shall also include the TCB call identifier,
parameter types (e.g., input, output), the effect
of the call, TCB call conventions (e.g., parameter
order, call sequence requirements), and exceptions
handled and signaled. It shall be shown to be an
accurate description of the TCB interface.
The DIS shall include those components of the TCB
that are implemented as hardware and/or firmware
if their properties are visible at the TCB
interface.
If the TCB consists of a kernel and privileged
processes, the developer shall separately identify
and define the interfaces for the kernel and each
privileged process.
The TCB interface definition must also include all
effects of a call including the direct visibility
and alterability of internal TCB variables and
functions.
Requirements for TCB Modular Decomposition
MD-3: Module Relationship Analysis
The developer shall design the TCB as a small
number (e.g., 10 to 100) of design and
implementation subsystems that have well-defined
functional relationships and shared-data
dependencies. The developer shall identify the
specific TCB protection properties and functions
associated with each subsystem and the TCB
interfaces (if any) implemented by each subsystem.
The developer shall design each subsystem as a set
of modules. For each module, the developer shall
describe: the role or purpose of the module, the
set of related functions performed by the module,
and the module interface (i.e., the set of
invocable functions, calling conventions,
parameters, global variables, and results). The
developer shall identify the protection functions
of, and describe the interfaces between, these
modules. The developer shall choose the modules so
that the set of functions implemented by the
module, the module's contribution to the TCB
protection properties, and the interface(s) to the
module can be described concisely (e.g., the
module shall have a single purpose). The TCB
structuring into modules shall be based on well-
defined module relationships; for example, the
contains relation (e.g., A is part of B), the
"uses" relation (e.g., A is correct only if B is
correct). The developer shall analyze the
correctness dependencies among these modules. This
analysis may include, but is not restricted to,
service and environmental dependencies.
Requirements for TCB Structuring Support
SP-3: Structured Protection Mechanisms
The TCB shall maintain process isolation. The TCB
shall separate those elements that are protection-
critical from those that are not. Features in
hardware, such as segmentation, shall be used to
support logically distinct storage objects with
separate access-control attributes (e.g.,
readable, writable). The TCB shall employ a
complete, conceptually simple, protection
mechanism with precisely defined semantics. This
mechanism shall play a central role in enforcing
the internal structuring of the TCB and the
product.
Requirements for Design Disciplines
DD-2: Extended Disciplines for TCB Structuring
The developer shall design the product to minimize
the complexity of the TCB. System engineering
shall be directed towards excluding from the TCB
modules that are not protection critical.
The TCB design shall reflect use of modern
software engineering techniques), such as data
hiding and abstraction (i.e., data, functional,
and control abstractions) and well-defined
exception-handling. The TCB design shall also
include use of layering (including a rationale for
each layering violation), high-level
synchronization constructs, and multi-tasking/
multi-threading.
Requirements for TCB Implementation Support
IM-3: Module Correspondence Support
The developer shall maintain engineering diagrams
and source code (as applicable) for all TCB
elements. The diagrams and source code for each
module of the TCB shall be identified and provided
as configuration items.
Requirements for Developer Functional Testing
FT-3: Specification-Driven TCB Interface Testing
The developer shall test the TCB interface to show
that all claimed protection functions work as
stated in the TCB interface description or
specification. The tests shall exercise the
boundary conditions of the protection functions.
The developer shall generate the test conditions
and data from the Descriptive Interface
Specification(s). The developer test procedures
shall include the tests used to demonstrate the
absence of all flaws discovered in previous
versions of the TCB.
The developer shall correct all flaws discovered
by testing and shall retest the TCB to show that
all discovered flaws have been eliminated, no new
flaws have been introduced, and the protection
functions work as claimed.
Requirements for Penetration Analysis
PA-2 Flaw-Hypothesis Testing
The developer shall define the TCB configuration,
interface, and protection functions that are
subject to penetration testing. For each test, the
developer shall identify the goal of the test and
the criteria for successful penetration. The
developer shall illustrate how, in addition to
system reference manuals and TCB interface
description, the DIS, source code, and hardware
and firmware specifications are used to define
penetration-test conditions. For each test, the
developer shall document all test conditions, data
(e.g., test set-up, function call parameters, and
test outcomes), and coverage.
The developer shall generate the test conditions
from flaw-hypotheses derived by negating
assertions of TCB design capabilities and by
providing counter examples that show that these
assertions are false. The developer shall confirm
the flaw hypotheses by checking design and
implementation documentation, by defining the test
data and running test programs, or by referring to
known classes of penetration flaws found in other
TCBs. The refutation of any hypothesis shall be
documented.
For each uncovered flaw, the developer shall
define and document scenarios of flaw exploitation
and shall identify all penetration outcomes
resulting from that scenario. The cause of the
flaw shall be identified and documented.
Requirements for Covert-Channel Analysis
CCA-2 Timing Channel Analysis
1. Identification: The developer shall identify
all sources of information used in covert-channel
analysis. These sources shall include TCB
reference manuals and DIS. The sources of
information and methods of identification shall
include processor specifications whenever the
identification method includes source code and
hardware analysis. The developer shall define the
identification method used. The developer shall
demonstrate that the chosen identification method
is sound (e.g., it leads to the discovery of all
covert channels in the DIS or source
documentation) and repeatable (i.e., independent
evaluators can use the method on the same sources
of covert-channel information and can obtain the
same results.) The developer shall define
scenarios of use for each covert channel. The
developer shall also define timing channel
scenarios, and shall identify all functions that
provide independent sources of timing (e.g., CPUs,
I/O processors).
2. Bandwidth Measurement or Engineering
Estimation: The developer shall define the method
used for covert-channel bandwidth estimation. In
measuring TCB performance for covert-channel-
bandwidth estimation, the developer shall satisfy
the following assumptions. The maximum bandwidth
estimation shall be based on the assumptions that
the covert channel is noiseless, that the senders
and receivers are not delayed by the presence of
other processes in the product, and that the
sender-receiver synchronization time is
negligible. The choice of informal estimation
methods shall define and justify the coding method
and, therefore, the distribution of "0s" and "1s"
in all transmissions.
The developer shall select TCB primitives to be
measured for bandwidth determination from real
scenarios of covert-channel use. The developer
shall specify TCB measurement environment for the
bandwidth measurements. This specification shall
include: (1) the speed of the product functions,
(2) the product configuration, (3) the sizes of
the memory and cache components, and (4) the
product initialization. The sensitivity of the
measurement results to configuration changes shall
be documented. The covert-channel measurements
shall include the fastest TCB function calls for
altering, viewing, and setting up the transmission
environment; the demonstrably fastest process
(context) switch time shall also be included in
the bandwidth measurements. All measurements shall
be repeatable.
3. Covert Channel Testing: The developer shall
test all the use of all identified covert channels
to determine whether the handling functions work
as intended.
Requirements for User Guidance
UG-1: Users' Guide
The developer shall provide a User Guide which
describes all protection services provided and
enforced by the TCB. The User Guide shall describe
the interaction between these services and provide
examples of their use. The User Guide may be in the
form of a summary, chapter or manual. The User
Guide shall specifically describe user
responsibilities. These shall encompass any user
responsibilities identified in the protection
profile.
Requirements for Administrative Guidance
AG-3: Role-Based Administrative Guidance
The developer shall provide a Trusted Facility
Manual intended for the product administrators and
operators that describes how to use the TCB
security services (e.g., Access Control, System
Entry, or Audit) to enforce a system security
policy. The Trusted Facility Manual shall include
the procedures for securely configuring, starting,
maintaining, and halting the TCB. The Trusted
Facility Manual shall explain how to analyze audit
data generated by the TCB to identify and document
user and administrator violations of this policy.
The Trusted Facility Manual shall explain the
unique security-relevant privileges and functions
of administrators and operators. The Trusted
Facility Manual shall also explain the distinct
security-relevant privileges and functions of the
TCB and how they can be selectively granted to
provide fine-grained, multi-person or multi-role
system and application administration policies.
The Trusted Facility Manual shall describe the
administrative interaction between security
services.
The Trusted Facility Manual shall identify all
hardware, firmware, software, and data structures
comprising the TCB. The detailed audit record
structure for each type of audit event shall be
described. The Trusted Facility Manual shall
explain how to configure the product to mitigate,
eliminate, or audit covert channel exploitation.
The Trusted Facility Manual shall describe the
cautions about and procedures for using the TCB as
a base for site-specific secure applications. The
Trusted Facility Manual shall describe procedures
for securely regenerating the TCB after any part
is changed (e.g., due to adding devices or
installing flaw corrections to the TCB software).
The Trusted Facility Manual shall be distinct from
User Guidance, and encompass any administrative
responsibilities identified in security
management.
Requirements for Trusted Generation
TG-3: Trusted Generation With Secure State Review
The developer shall establish and document the
procedures that a consumer must perform to
generate an operational TCB from the delivered
copy of the master TCB. The consumer documentation
shall identify any system parameters, which are
initialized or set during system generation, that
affect the TCB's conformance to the protection
profile and state the acceptable ranges of values
for those parameters. The product shall be
delivered with each of these parameters set to its
fail-safe defaults. The developer shall provide
the consumer with a capability to review the
product security state (e.g., by providing a
program, which could be executed after generating
and starting the TCB, that determines the
consistency of the protection-relevant
parameters).
Requirements for Life Cycle Definition
LC-3: Measurable Life Cycle Process
The developer shall develop and maintain the
product using a well defined, standardized, and
measurable engineering process. The developer
shall explain why the process was chosen and how
the developer uses it to develop and maintain the
product. The developer shall comply with the
engineering process standard. The process shall
incorporate a security policy that states the
technical, physical, procedural, personnel, and
other measures used by the developer to protect
the product and its documentation. The developer
shall demonstrate that each development process
and support process requirement of the protection
profile is satisfied by some part, or parts, of
the developer's process. The developer shall
identify the programming languages used to develop
the TCB software and reference the definitions of
those languages. The developer shall identify any
implementation dependent options of the
programming language compiler(s) used to implement
the TCB software and reference the definitions of
those languages.The developer shall describe
coding standards followed during the
implementation of the product and shall ensure
that all source code complies with these
standards.
Requirements for Configuration Management
CM-3: Comprehensive Automated Control
The developer shall establish configuration
control and generation procedures employing
automated tools for developing and maintaining the
TCB. The procedures shall be employed to ensure
that changes to the TCB are consistent with the
product's protection properties and security
policy. The developer shall employ these tools to
track and control changes to development evidence,
implementation data (e.g., source code and
hardware diagrams), executable versions of the
TCB, test documentation and procedures, identified
flaws, and consumer documentation. The procedures
shall include a formal acceptance process for
protection-relevant changes.
The configuration control procedures shall assure
a consistent mapping among documentation and code
associated with the current version of the TCB and
permit the regeneration of any supported version
of the TCB. The developer shall provide tools for
the generation of a new version of the TCB from
source code. Also, tools shall be available for
comparing a newly generated version with the
previous TCB version to ascertain that only the
intended changes have been made in the code that
will actually be used as the new version of the
TCB.
Requirements for Evidence of TCB Protection Properties
EPP-3 Evidence of Formal Model Interpretation in the DIS
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. This documentation shall
describe how the TCB implements the reference
monitor concept. The developer shall also provide
a formal access-control model and an informal
reference mediation and TCB protection model. The
TCB properties, which are defined by this
correspondence and the interpretation of these
models within the DIS of the TCB shall be
documented by the product developer.
Requirements for Evidence of Product Development
EPD-4: Policy Consistency Of The DIS
The developer shall provide TCB Design
Specifications that include: a list of the TCB
elements (hardware, software, and firmware
configuration items); a list of protection
services provided to the TCB by hardware,
software, and firmware that is not part of the
TCB; an explanation of the techniques and criteria
used during the modular decomposition of the TCB;
a description of the policy allocations,
functions, and interactions among the major TCB
subsystems; and module level descriptions of all
software and hardware in the TCB.
The developer shall provide a Descriptive
Interface Specification (DIS) that describes the
functions, effects, exceptions and error messages
visible at the TCB interface and includes a
convincing argument that the DIS is consistent
with the formal model of the policy. The developer
shall show that the DIS is an accurate
representation of the TCB's external interfaces.
The developer shall provide TCB Implementation
Data consisting of the engineering diagrams for
all hardware included in the TCB and the source
code used to generate the TCB software and
firmware. The developer shall show that the TCB
software, firmware, and hardware implement the
documented TCB design.
Requirements for Evidence of Functional Testing
EFT-3: Evidence of Specification-Driven Testing
The developer shall provide evidence of the
functional testing that includes the test plan,
the test procedures, and the results of the
functional testing. The test, plans, procedures,
and results shall be maintained under the same
configuration control as the TCB software. The
test plans shall identify the TCB specification
used in the derivation of the test conditions,
data, and coverage analysis.
Requirements for Evidence of Penetration Analysis
EPA-2: Evidence of Flaw-Hypothesis Generation and Testing
The developer shall provide evidence of
penetration testing. The penetration evidence
shall identify all product documentation and
development evidence on which the search for flaws
was based. The penetration evidence shall describe
the scenarios for exploiting each potential flaw
in the system and the penetration test conditions,
data (e.g., test set-up, function call parameters,
and test outcomes), coverage, and conclusions
derived from each scenario. The penetration
evidence shall summarize both refuted and
confirmed flaws hypothesis.
Requirements for Evidence of Covert Channel Analysis
ECC-2: Evidence of Covert Channel Analysis and Handling
The developer's documentation shall present the
results of the covert channel analysis and the
trade-offs involved in restricting these channels.
All auditable events that may be used in the
exploitation of known covert channels shall be
identified. The developer shall provide the
bandwidths of known covert channels whose use is
not detectable by the auditing mechanism. The
documentation of each identified covert channel
shall consist of the variables, timing sources,
and the TCB interface functions that can be used
to transmit information. The measurements of each
TCB function call used by covert channels must be
documented and the bandwidth computation shall be
included for each channel. The measurement
environment should be documented as specified.
Test documentation shall include results of
testing the effectiveness of the methods used to
reduce covert-channel bandwidths.
Requirements for Evidence of Product Support
EPS-3: Evidence of Measured Product Support
The developer shall provide documentation that
defines, explains, and justifies the policies,
procedures, plans, and tools established by the
developer to satisfy the Operational Support and
Development Environment requirements of the
protection profile. The documentation shall also
explain how the developer periodically evaluates
compliance with the established procedures,
policies, and plans.
Requirements for Test Analysis
TA-4: Comprehensive Test Analysis
The evaluator shall assess whether the producer
has performed the activities defined in the
development assurance requirements of the
protection profile for functional testing and
penetration analysis, and whether the producer has
documented these activities as defined in the
development evidence requirements of the
protection profile. The evaluator shall analyze
the results of the producer's testing activities
for completeness of coverage and consistency of
results, and general correctness (e.g., defect
trend from regression testing). This analysis
shall examine the testability of requirements, the
adequacy of the tests to measure the required
properties, the deviation of the actual results
obtained from the expected results. The analysis
shall extend to trace all defects identified,
corrected, and retested. The analysis shall
include an assessment of test coverage and
completeness, and defect frequency. The results of
testing shall be interpreted in terms that express
product performance and protection adequacy. The
evaluator shall determine whether the product's
protection properties, as defined for all
protection-relevant modules of the TCB, and all
relevant known penetration flaws have been tested.
The evaluator shall independently develop, test,
and document additional flaw hypotheses. The
evaluator shall assess testing results to
determine whether the product's TCB works as
claimed, that the TCB's implementation is
consistent with the DIS, and whether there are any
obvious ways (i.e., ways that are known, or that
are readily apparent or easily discovered in
product documentation) for an unauthorized user to
bypass the policy implemented by the TCB or
otherwise defeat the product's TCB, and whether
all discovered TCB flaws have been corrected and
no new TCB flaws introduced. No design flaws and
no more than a few correctable implementation
flaws may be found during testing and there shall
be reasonable confidence that few remain. The
testing results shall show that the methods used
to reduce covert channel bandwidths have been
effective for all evaluated configurations. The
evaluator shall determine whether the product is
relatively resistant to penetrations.
Requirements for Independent Testing
IT-3: Comprehensive Independent Testing.
The evaluator shall independently perform
functional and elementary penetration testing to
confirm test results. This testing may be
selective and shall be based on (1) the results of
other independent and/or producer testing, (2) the
TCB's DIS, (3) other product design and
implementation documentation, (4) the product's
user and administrative documentation, (5)
relevant known penetration flaws, and (6)
evaluator-developed TCB penetration flaw
hypotheses and corresponding tests that attempt to
exploit the hypothesized flaws. Satisfactory
completion consists of demonstrating that all TCB
functions work as described in the product's
relevant documentation, that test results are
consistent, and that no discrepancies exist
between the documentation and the product.
Satisfactory penetration test completion shall be
determined by the subjective judgement (which may
be supported algorithmically) of the evaluator.
Test duration agreements may further constrain
this judgement. Categorization of an actual
penetration flaw shall be based on the
reproducibility of that flaw. Flaws that are
discovered, but are not reproducible shall remain
categorized as potential penetration flaws. All
actual penetration flaws must be corrected and
retested.
The evaluator shall provide a penetration test
plan document that describes the additional
evaluator-developed flaw hypotheses and associated
tests. The evaluator shall execute these tests and
shall report any discovered flaws to the producer
as part of the testing results. At the conclusion
of penetration testing, the evaluator shall
provide copies of this penetration test plan and
its test results to the producer. The producer
shall ensure that this test plan and its test
results are incorporated into the rest of the
product's testing documentation and that such
documentation is available for further analysis
throughout the life of the product.
The evaluator shall test for covert channel
bandwidth reductions to determine the
effectiveness of handling method(s) in reducing
the bandwidths of identified covert channels for
all evaluated configurations.
If the independent testing is performed at beta-
test sites, the producer shall supply the beta-
test plan and the test results. The evaluator
shall review the scope and depth of beta testing
with respect to the required protection
functionality, and shall verify independence of
both the test sites and the producer's and beta-
test user's test results. The evaluator shall also
confirm that the test environment of the beta-test
site(s) adequately represents the environment
specified in the protection profile.
Requirements for Development Environment
DER-3: Comprehensive Development Environment Review
The evaluator shall review the producer's
development and maintenance process description
documentation and shall conduct a complete audit
of the producer's processes using the evidence
generated by each process to determine the degree
of discipline enforced upon and within the
process, and to determine the protection
characteristics associated with the product's
development and maintenance. The results of this
review shall establish, for the evaluator, the
producer's development environment, its policies,
and the degree of enforcement maintained during
development execution. The review shall also
confirm the producer's complete conformance with
all relevant development environment requirements.
Requirements for Operational Support
OSR-3 Comprehensive Operational Support Review
The evaluator shall review all documentation
focused on the activities of product use (e.g.,
Users Manuals) and product administration
including installation, operation, maintenance,
and trusted recovery (e.g., Trusted Facility
Management manuals. This review shall assess the
clarity of presentation, difficulty in locating
topics of interest, ease of understanding, and
completeness of coverage. The need for separate
manuals dedicated to protection-relevant aspects
of the product should be assessed for
effectiveness. The evaluator shall execute all
documented protection-relevant features and
procedures to determine if their descriptions are
accurate and correct.
Requirements for Design Analysis
DA-3: Comprehensive Design Analysis
The evaluator shall determine whether the producer
has performed the activities defined in the
development process assurance requirements of the
protection profile for TCB property definition and
TCB design. The evaluator shall determine whether
the producer has documented these activities as
defined in the development evidence requirements
of the protection profile. The evaluator shall
analyze, with the help of formal methods and
appropriate automated tools, the results of the
producer's activities for completeness,
consistency, and correctness of design with
respect to requirements (e.g., validating the
formal verification of the design).
Requirements for Implementation
CI-3: Comprehensive Implementation Analysis
The evaluator shall conduct an inspection on a
moderate sample of randomly selected product code.
The assessment shall focus on the clarity of the
coding style, adherence to coding standards,
coding documentation, and on possible software
defects that may be present with respect to the
product's formal design and model. The inspection
shall be performed to obtain only a sample of
possible software defects, not to capture all such
possible defects. The evaluator shall report all
discovered defects to the producer; the assessment
shall report the number of defects found per line
of code inspected from the random sample size. Use
of producer-provided code inspection results can
supplement this inspection. All trapdoors built
into the product for maintenance purposes shall be
identified by the producer and shown to be
protected by the product. The producer shall
correct all discovered defects and the corrected
software reinspected. A rigorous analysis of the
implementation's correspondence to the verified
design shall be performed by the evaluator to
validate correctness. Such analysis may be
supported by appropriate automated tools.
DRAFT
LABEL BASED PROTECTION
FOR
MULTI-USER INFORMATION SYSTEMS
LEVEL 4
(LP-4)
A Protection Profile
Derived from the Federal Criteria for IT Security
Version 1.0
December 1992
This document is undergoing review and
is subject to modification or withdrawal.
The contents of this document should not
be referenced in other publications.
Supersedes the
Trusted Computer System Evaluation Criteria
Class A1
DRAFT
LABEL-BASED PROTECTION - 4 (LP-4)
This Protection Profile has been developed to define a set
of technical measures that can be incorporated into remote-
access, resource- and information-sharing Information
Technology (IT) products that will be used to protect two or
more levels of National Security Information classified
according to US Executive Order 12356 (EO 12356). This profile
can also be used to protect any information that has been
designated as sensitive information for which information
separation and access are based on sensitivity markings
applied to the information. This profile is intended for use
in environments where the presence potentially malicious
application software (e.g., Trojan Horses) mandate the use of
high-assurance products.
Compliant IT products will provide highly-structured,
conceptually simple protection mechanisms for a multi-level
information processing environment with which an organization
can construct an automated information system to enhance or
optimize the organization's ability to perform its mission.
Formal assurance of security policy support and covert channel
analysis must be available. Compliant IT products are
maintained under very strict configuration management
facilities and can only be distributed via a trusted
distribution channel.
LP-4 compliant products are functionally equivalent to
those satisfying profile LP3 in that no additional
architectural features or policy requirements are added. The
distinguishing feature of systems in this class is the
analysis derived from formal design specifications and
verification techniques and the resulting high degree of
assurance that the TCB is correctly implemented. This
assurance is developmental in nature, starting with a formal
model of the security policy and a formal interface
specification (FIS) of the design. Independent of the
particular specification language or verification system
used, there are five important criteria for profile LP-4
design verification:
a. A formal model of the security policy must be clearly
identified and documented, including a mathematical
proof that the model interpretation in the TCB is
valid (i.e., the model interpretation is consistent
with the model axioms) and is sufficient to support
the security policy.
b. A FIS must be produced that includes abstract
definitions of the functions the TCB performs and of
the hardware and/or firmware mechanisms that are used
to support separate execution domains.
c. The FIS of the TCB must be shown to be consistent with
the model by formal techniques where possible (i.e.,
where verification tools exist) and informal ones
otherwise.
d. The TCB implementation (i.e., in hardware, firmware,
and software) must be informally shown to be
consistent with the FIS. The elements of the FIS must
be shown, using informal techniques, to correspond to
the elements of the TCB. The FIS must express the
unified protection mechanism required to satisfy the
security policy, and it is the elements of this
protection mechanism that are mapped to the elements
of the TCB.
e. Formal analysis techniques must be used to identify
and analyze covert channels. Informal techniques may
be used to identify covert timing channels. the
continued existence of identified covert channels in
the system must be justified.
In keeping with the extensive design and development
analysis of the TCB required of LP4 compliant systems,
stringent configuration management is required and procedures
are established for securely distributing the system to sites.
A system security administrator is supported.
Cross References:
o Existing Criteria:
(1) TCSEC: A1
(2) ITSEC
(3) CTCPEC
o Other Protection Profiles
(1) TBD
COMPONENT SUMMARY:
LP-4 Functional Component Summary
.--------------------------------------------.
| | Code & |
| Functional Component | Level |
|============================================|
| Security Policy Support |
|----------------------------------+---------|
| Accountability |
|----------------------------------+---------|
| Identification&Authentication | I&A-2 |
|----------------------------------+---------|
| System Entry | ---- |
|----------------------------------+---------|
| Trusted Path | TP-2 |
|----------------------------------+---------|
| Audit | AD-1+ |
|----------------------------------+---------|
| Access Control | AC-3+ |
|----------------------------------+---------|
| Discretionary | AC-3+ |
|----------------------------------+---------|
| Non-Discretionary | AC-3 |
|----------------------------------+---------|
| Covert Channel Handling | CCH-3 |
|----------------------------------+---------|
| Availability | ---- |
|----------------------------------+---------|
| Resource Allocation | ---- |
|----------------------------------+---------|
| Fault Tolerance | ---- |
|----------------------------------+---------|
| Security Mgmt. | SM-1++ |
|----------------------------------+---------|
| Reference Mediation | RM-3 |
|----------------------------------+---------|
| TCB Logical Protection | P-3 |
|----------------------------------+---------|
| TCB Physical Protection | ---- |
|----------------------------------+---------|
| TCB Self-checking | SC-1 |
|----------------------------------+---------|
| TCB Start-Up and Recovery | TR-1 |
|----------------------------------+---------|
| TCB Privileged Operation | PO-2 |
|----------------------------------+---------|
| TCB Ease-of-Use | ---- |
`--------------------------------------------'
LP-4 Assurance Component Summary
.---------------------------------------.
| Assurance Components | T7 |
|================================|======|
| Development Assurance Components |
|=======================================|
| Development Process |
|--------------------------------+------|
| TCB Property Definition | PD-4 |
|--------------------------------+------|
| TCB Design |
|--------------------------------+------|
| TCB Element Identification | ID-2 |
|--------------------------------+------|
| TCB Interface Definition | IF-3 |
|--------------------------------+------|
| TCB Modular Decomposition | MD-3 |
|--------------------------------+------|
| TCB Structuring Support | SP-3 |
|--------------------------------+------|
| TCB Design Disciplines | DD-2 |
|--------------------------------+------|
| TCB Implementation Support | IM-4 |
|--------------------------------+------|
| TCB Testing and Analysis |
|--------------------------------+------|
| Functional Testing | FT-3 |
|--------------------------------+------|
| Penetration Analysis | PA-2 |
|--------------------------------+------|
| Covert Channel Analysis | CCA3 |
|--------------------------------+------|
| Operational Support |
|--------------------------------+------|
| User Security Guidance | UG-1 |
|--------------------------------+------|
| Administrative Guidance | AG-3 |
|--------------------------------+------|
| Trusted Generation | TG-3 |
|--------------------------------+------|
| Development Environment |
|--------------------------------+------|
| Life Cycle Definition | LC-3 |
|--------------------------------+------|
| Configuration Management | CM-4 |
|--------------------------------+------|
| Trusted Distribution | TD-1 |
|--------------------------------+------|
| Development Evidence |
|--------------------------------+------|
| TCB Protection Properties | EPP4 |
|--------------------------------+------|
| Product Development | EPD5 |
|--------------------------------+------|
| Product Testing & Analysis |
|--------------------------------+------|
| Functional Testing | EFT3 |
|--------------------------------+------|
| Penetration Analysis | EPA2 |
|--------------------------------+------|
| Covert Channel Analysis | ECC2 |
|--------------------------------+------|
| Product Support | EPS3 |
`---------------------------------------'
|=======================================|
| Evaluation Assurance Components |
|=======================================|
| Testing |
|--------------------------------+------|
| Test Analysis | TA-5 |
|--------------------------------+------|
| Independent Testing | IT-4 |
|--------------------------------+------|
| Review |
|--------------------------------+------|
| Development Environment | DER3 |
|--------------------------------+------|
| Operational Support | OSR3 |
|--------------------------------+------|
| Analysis |
|--------------------------------+------|
| Protection Properties | ---- |
|--------------------------------+------|
| Design | DA-3 |
|--------------------------------+------|
| Implementation | CI-3 |
`---------------------------------------'
RATIONALE
16. Information Protection Policy
It is anticipated that organizations wishing to process
two to three levels of classified information with multiple
categories will want to use IT products that are compliant
with this profile in their automated information processing
systems. These organizations should be able to trust the
profile-compliant IT product to contribute to the protection
of the classified information at least as much as they trust
the properly cleared personnel who are using and managing the
system.
17. Protection Philosophy
This profile presumes a hostile environment with divided,
aggressive users. It provides control of access to shared
resources both (1) on the basis of attributes that are
controlled by the ordinary users of the system and (2) on the
basis of attributes that are controlled only by the system
administrators.
Profile compliant IT products will minimally meet the
following objectives:
a. Employ a reference validation mechanism to enforce a
formally defined security policy that describes the
rules for controlling access to system subjects and
objects and use the access control rules to enforce an
information flow policy that aims to control the use
of covert storage and timing channels.
b. Associate explicit sensitivity labels with each
subject and object in the system and each port through
which information may be exported from or imported to
the system. Maintain the accuracy of the sensitivity
labels as information moves within the system and
through the ports.
c. Authenticate the claimed identity of each external
human user of the IT product prior to establishing any
internal entity to act on behalf of that user and
firmly bind the authenticated user identity to the
internal entity.
d. Selectively keep and protect a log of all actions or
events (including use of covert storage channels) that
could affect system security so that they can be
accurately attributed to the known user or system
entity responsible for causing the action or event.
Also, alert the system administrator when a series of
events indicates an imminent violation of the security
policy.
e. Contains hardware and software mechanisms that can be
independently evaluated to provide sufficient
assurance that the system satisfies the previous four
objectives.
f. Implements the enforcement of objectives a through d
in such a fashion that the enforcing mechanisms are
protected from tampering and unauthorized changes by
the information moving entities that the mechanisms
are supposed to control.
18. Expected Threats
The requirements for profile conforming IT products assume
that these products are being used in an environment where
there are different levels and categories of classified data
and users of differing clearance levels. A conforming IT
product can be reasonably expected to protect the
confidentiality of information in an environment where there
are three levels and multiple categories of classified data,
and two or more levels of cleared users and where there are
collaborating, malicious users and software at each clearance
level.
19. Assumed Environment
19.1 Characteristics
IT products complying with the requirements set forth in
this profile are expected to be used in an environment with
the following characteristics:
a. Multiple users will be accessing the operating system
at the same time.
b. The IT product hardware base (e.g., CPU, printers,
terminals, etc.) is protected from unauthorized
physical access.
c. One or more personnel are assigned to manage the
system in which the IT product is incorporated,
including the security of the information it contains.
d. A need to control user access to information exists
and is based on an explicit sensitivity marking
associated with the information (e.g, Secret or Top
Secret).
e. There is a need to control user access to information
exists and is based on that user's identity and
membership in organizations or groups.
f. The IT product provides facilities for some or all of
the authorized users to create programs that use the
applications programming interface (API) and make
those programs available to other users.
g. The IT product is used to provide a cooperative
environment for the users to accomplish some task or
group of tasks.
19.2 Environment Dependencies
Secure installation and operation of a product satisfying
these profile requirements depends on provision of a number
of elements in the installation environment. These include:
a. Physical security must be provided. For US Government
classified operation, physical security equivalent to
PP-2 would be required.
b. Cabling to other devices must be shown to be
consistent with policy implemented by the product. For
example, a "port" in the product is required to have
an assigned label. No device can be connected to the
port unless it has been established externally that
the device is allowed to receive data with the same
label.
c. Personnel allowed to access data processed by the
installed product must already be authorized for such
access.
20. Intended Use
Conforming IT products are useful in both general-purpose
office automation environments with multiple data
sensitivities (or "classifications") and multiple levels of
user authorizations (or "clearances") and in specialized
computing, network and mission environments. Examples of the
office automation environment might include military
headquarters and highly competitive procurement offices.
Examples of the network environments include use as the basis
for a multilevel secure network management center or a trusted
guard gateway operating between two networks processing
different levels of information. An example of the specialized
mission environment might be as a platform for a portable
battlefield map and mission management application.
FUNCTIONAL REQUIREMENTS
Requirements for Identification and Authentication
I&A-2 Identification, Authentication, and Authorization
1. The TCB shall require users to identify
themselves to it before beginning to perform any
other actions that the TCB is expected to mediate.
The TCB shall be able to enforce individual
accountability by providing the capability to
uniquely identify each individual user. The TCB
shall also provide the capability of associating
this identity with all auditable actions taken by
that individual.
2. The TCB shall maintain authentication data that
includes information for verifying the identity of
individual users (e.g., passwords) as well as
information for determining the clearance and
authorization of individual users. These data
shall be used by the TCB to authenticate the
user's identity and to ensure that the subject
security level and authorizations of subjects
external to the TCB that may be created to act on
behalf of the individual user are dominated by the
clearance and authorization of that user).
3. The TCB shall protect authentication data so
that it cannot be used by any unauthorized user.
Requirements for Trusted Path
TP-2 Trusted User-to-TCB Communication
The TCB shall support a trusted communication path
between itself and users for use whenever a
positive user-to-TCB connection is required (e.g.,
login, change of policy attributes).
Communications via this trusted path shall be
activated exclusively by a user or the TCB and
shall be logically isolated and unmistakably
distinguishable from other communication paths.
Requirements for Audit
AD-1+ Minimal Audit
1. The TCB shall be able to create, maintain, and
protect from modification or unauthorized access
or destruction an audit trail of accesses to the
objects it protects. The audit data shall be
protected by the TCB so that read access to it is
limited to those who are authorized for audit
data.
2. The TCB shall be able to record the following
types of events:
- use of the identification and authentication
mechanisms;
- introduction of objects into a user's address
space (e.g., file open, program initiation), and
deletion of objects;
- actions taken by computer operators and system
administrators and/or system security officers.
The TCB shall be able to record any override of
human-readable output markings. The TCB shall also
be able to audit the identified event that may be
used in the exploitation of covert channels.
The TCB shall contain a mechanism that is able to
monitor the occurrence or accumulation of
auditable events that may indicate an imminent
violation of the product's security policy. This
mechanism shall be able to immediately notify the
security administrator when thresholds are
exceeded, and, if the occurrence or accumulation
of these security relevant events continues, the
system shall take the least disruptive action to
terminate the event. [AD-3]
3. For each recorded event, the audit record shall
identify: date and time of the event, user, type
of event, and success or failure of the event. For
identification/authentication events the origin of
request (e.g., terminal ID) shall be included in
the audit record. For events that introduce an
object into a user's address space and for object
deletion events the audit record shall include the
name and the object security level.
4. The system administrator shall be able to
selectively audit the actions of one or more users
based on individual identity and/or object
security level.
Requirements for Access Control
AC-3 + Extended Access Control
1. Definition of Access Control Attributes
The TCB shall define and protect access control
attributes for subjects and objects. Subject
attributes shall include named individuals or
defined groups or both. Object attributes shall
include defined access rights (e.g., read, write,
execute) that can be assigned to subject
attributes. Access control attributes
corresponding to each individual policy shall be
identified.
Sensitivity labels associated with each subject
and storage object that is directly or indirectly
accessible by subjects external to the TCB shall
be maintained by the TCB. The sensitivity labels
shall be used as the basis for mandatory access
control decisions.
The subjects and objects shall be assigned
sensitivity labels that are a combination of
hierarchical classification levels and non-
hierarchical categories, and the labels shall be
used as the basis for mandatory access control
decisions. The TCB shall be able to support two or
more such security levels.
The subject and object attributes shall accurately
reflect the sensitivity and integrity of the
subject or object. When exported by the TCB,
sensitivity labels shall accurately and
unambiguously represent the internal labels and
shall be associated with the information being
exported.
The TCB shall immediately notify a terminal user
of each change in the security level associated
with that user during an interactive session. A
terminal user shall be able to query the TCB as
desired for a display of the subject's complete
sensitivity label.
The TCB shall support the assignment of minimum
and maximum security levels to all attached
physical devices. These security levels shall be
used by the TCB to enforce constraints imposed by
the physical environments in which the devices are
located.
2. Administration of Access Control Attributes
The TCB shall define and enforce rules for
assignment and modification of access control
attributes for subjects and objects. The effect of
these rules shall be that access permission to an
object by users not already possessing access
permission is assigned only by authorized users.
These rules shall allow authorized users to
specify and control sharing of objects by named
individuals or defined groups of individuals, or
by both, and shall provide controls to limit
propagation of access rights. (i.e., these rules
shall define the distribution, revocation, and
review of access control attributes). The controls
defined by these rules shall be capable of
specifying for each named object, a list of
individuals and a list of groups of named
individuals, with their respective access rights
to that object. Furthermore, for each named
object, it shall be possible to specify a list of
named individuals and a list of groups of named
individuals for which no access to the object is
given [AC-4}. These controls shall be capable of
including or excluding access to the granularity
of a single user.
The rules for assignment and modification of
access control attributes shall include those for
attribute assignment to objects during import and
export operations.
Export of Labeled Information
The TCB shall designate each communication
channel and I/O device as either single-level or
multilevel. Any change in this designation shall
be done manually and shall be auditable by the
TCB. The TCB shall maintain and be able to audit
any change in the security level or levels
associated with a communication channel or I/O
device.
1. Exportation to Multilevel Devices
When the TCB exports an object to a multilevel
I/O device, the sensitivity label associated with
that object shall also be exported and shall
reside on the same physical medium as the exported
information and shall be in the same form (i.e.,
machine-readable or human-readable form). When the
TCB exports or imports an object over a multilevel
communication channel, the protocol used on that
channel shall provide for the unambiguous pairing
between the sensitivity labels and the associated
information that is sent or received.
2. Exportation to Single-Level Devices
Single-level I/O devices and single-level
communication channels are not required to
maintain the sensitivity labels of the information
they process. However, the TCB shall include a
mechanism by which the TCB and an authorized user
reliably communicate to designate the single
security level of information imported or exported
via single-level communication channels or I/O
devices.
3. Labeling Human-Readable Output
The system administrator shall be able to
specify the printable label names associated with
exported sensitivity labels. The TCB shall mark
the beginning and end of all human-readable,
paged, hardcopy output (e.g., line printer output)
with human-readable sensitivity labels that
properly represent the sensitivity of the output.
The TCB shall, by default, mark the top and bottom
of each page of human-readable, paged, hardcopy
output (e.g., line printer output) with human-
readable sensitivity labels that properly
represent the overall sensitivity of the output or
that properly represent the sensitivity of the
information on the page. The TCB shall, by default
and in an appropriate manner, mark other forms of
human-readable output (e.g., maps, graphics) with
human-readable sensitivity labels that properly
represent the sensitivity of the output. Any
override of these marking defaults shall be
auditable by the TCB.
Import of Non-labeled Data
In order to import non-labeled data, the TCB
shall request and receive from an authorized user
the security level of the data, and all such
actions shall be auditable by the TCB.
If different rules of assignment and modification
of access control attributes apply to different
subjects and/or objects, the totality of these
rules shall be shown to support the defined
policy.
3. Authorization of Subject References to Objects
The TCB shall define and enforce authorization
rules for the mediation of subject references to
objects. These rules shall be based on the access
control attributes of subjects and objects. These
rules shall, either by explicit user action or by
default, provide that objects are protected from
unauthorized access.
The scope of the authorization rules shall include
all subjects, storage objects (e.g., processes,
segments, devices) and associated access control
attributes that are directly or indirectly
accessible to subjects external to the TCB. The
scope of the authorization rules shall also
include all policy and status attributes of
subjects and storage objects (e.g., quotas, object
existence, size, access time, creation and
modification time, locked/unlocked). If different
rules apply to different subjects and objects, the
totality of these rules shall be shown to support
the defined policy.
The authorization rules for the mandatory access
control policy shall include:
The TCB shall enforce a mandatory access control
policy over all resources (i.e., subjects, storage
objects, and I/O devices that are directly or
indirectly accessible by subjects external to the
TCB. The following requirements shall hold for all
accesses between all subjects external to the TCB
and all objects directly or indirectly accessible
by these subjects: A subject can read an object
only if the hierarchical classification in the
subject's security level is greater than or equal
to the hierarchical classification in the object's
security level and the non- hierarchical
categories in the subject's security level include
all the non-hierarchical categories in the
object's security level. A subject can write an
object only if the hierarchical classification in
the subject's security level is less than or equal
to the hierarchical classification in the object's
security level and all the non-hierarchical
categories in the subject's security level are
included in the non-hierarchical categories in the
object's security level.
The authorization rules for each policy shall be
defined separately. The TCB shall define and
enforce the composition of policies, including the
enforcement of the authorization rules (e.g.,
subject and object type coverage, enforcement
precedence).
4. Subject and Object Creation and Destruction
The TCB shall control the creation and destruction
of subjects and objects. These controls shall
include object reuse. That is, all authorizations
to the information contained within a storage
object shall be revoked prior to initial
assignment, allocation or reallocation to a
subject from the TCB's pool of unused storage
objects; information, including encrypted
representations of information, produced by a
prior subjects' actions shall be unavailable to
any subject that obtains access to an object that
has been released back to the system.
Requirements for Covert Channel Handling
CCH-3 Timing Channel Audit and Bandwidth Limitation
1. The TCB and privileged applications shall
include functions that help audit the use of
covert storage channels. These functions shall
enable the identification of the transmitter,
receiver, and specific covert channels used (e.g.,
TCB and privileged application element used to
transmit information). TCB functions that help
limit the bandwidth and/or eliminate covert
storage channels shall also be provided. The
bandwidth limits for each channel shall be
settable by system administrators.
2. The functions added to the TCB and privileged
applications for storage channel auditing shall be
identified for each channel and shall be available
in common product configurations. If audit
functions are not added to certain storage
channels (e.g., hardware storage channels),
evidence must be provided to justify why these
channels do not represent a security threat for
the intended use of the product. TCB and
privileged application functions that help limit
the bandwidth and/or eliminate covert storage or
timing channels shall also be available in common
product configurations.
If channel bandwidth limitation and channel
elimination functions are not added to certain
storage or timing channels (e.g., hardware
channels), evidence must be provided to justify
why these channels do not represent a security
threat for the intended use of the product.
Requirements for Security Management
SM-1++ Minimal Security Management
1. The TCB shall provide an installation mechanism
for the setting and updating of its configuration
parameters, and for the initialization of its
protection-relevant data structures before any
user or administrator policy attributes are
defined. It shall allow the configuration of TCB
internal databases and tables.
2. The TCB shall provide protected mechanisms for
displaying and modifying the security policy
parameters.
3. The TCB shall provide protected mechanisms for
manually displaying, modifying, or deleting user
registration and account parameters. These
parameters shall include unique user identifiers,
their account, and their associated user name and
affiliation. The TCB shall allow the manual
enabling and disabling of user identities and/or
accounts.
4. The TCB shall support separate operator and
administrator functions. The operator functions
shall be restricted to those necessary for
performing routine operations. The operator
functions shall allow the enabling and disabling
of peripheral devices, mounting of removable
storage media, backing-up and recovering user
objects; maintaining the TCB hardware and software
elements (e.g., on-site testing); and starting and
shutting down the system. The administrative
functions shall support separate security
administrator and auditor roles. The TCB shall
enable the administrators to perform their
functions only after taking distinct auditable
action to assume an administrator role. Non-
security functions that can be performed in the
security administrative role shall be limited
strictly to those essential to performing the
security role effectively.[SM-4]
5. The use of the protected mechanisms for system
administration shall be limited to authorized
administrative users.
Requirements for Reference Mediation
RM-3 Mediation of References to Subject and Object
Attributes
1. The TCB shall mediate all references to
subjects, objects, resources, and services (e.g.,
TCB functions) described in the TCB
specifications. The mediation shall ensure that
all references are directed to the appropriate
security-policy functions.
2. Reference mediation shall include control of
references to all subjects, objects, and resources
protected under the TCB security policy, to their
policy (i.e., access rights, security levels) and
status attributes (e.g., existence, length,
locking state).
3. References issued by privileged subjects shall
be mediated in accordance with the policy
attributes defined for those subjects.
Requirements for Logical TCB Protection
P-3 TCB Isolation and Timing Consistency
The TCB shall maintain a domain for its own
execution that protects it from external
interference and tampering (e.g., by reading or
modification of its code and data structures). The
protection of the TCB shall provide TCB isolation
and noncircumventability of TCB isolation
functions as follows:
1. TCB Isolation requires that (1) the address
spaces of the TCB and those of unprivileged
subjects are separated such that users, or
unprivileged subjects operating on their behalf,
cannot read or modify TCB data structures or code,
(2) the transfers between TCB and non-TCB domains
are controlled such that arbitrary entry to or
return from the TCB are not possible; and (3) the
user or application parameters passed to the TCB
by addresses are validated with respect to the TCB
address space, and those passed by value are
validated with respect to the values expected by
the TCB.
2. Non-circumventability of TCB isolation
functions requires that the permission to objects
(and/or to non-TCB data) passed as parameters to
the TCB are validated with respect to the
permissions required by the TCB, and references to
TCB objects implementing TCB isolation functions
are mediated by the TCB.
TCB protection shall also maintain the consistency
of TCB global variables and eliminate undesirable
dependencies of the TCB on unprivileged subject or
user actions.
3. Consistency of TCB global variables requires
that consistency conditions defined over TCB
internal variables, objects, and functions hold
before and after any TCB invocation.
4. Elimination of undesirable dependencies of
the TCB on unprivileged subject actions requires
that any TCB invocation by an unprivileged subject
(or user) input to a TCB call may not place the TCB
in a state such that it is unable to respond to
communication initiated by other users.
Furthermore, TCB protection shall maintain the
timing consistency of condition checks.
5. Timing consistency of condition checks
requires that a validation check holds at the
instant when the TCB action depending on that
check is performed.
Requirements for TCB Self Checking
SC-1 Minimal Self Checking
Hardware and/or software features shall be
provided that can be used to periodically validate
the correct operation of the on-site hardware and
firmware elements of the TCB.
Requirements for TCB Start-Up and Recovery
TR-1 Minimal Requirements for Recovery or Start-up
Procedures and/or mechanisms shall be provided to
assure that, after a TCB failure or other
discontinuity, recovery without protection
compromise is obtained.
Requirements for TCB Privileged Operation
PO-2 Privilege Association with TCB Modules
1. TCB privileges needed by individual functions,
or groups of functions, of a functional component
shall be identified. Privileged TCB calls or
access to privileged TCB objects, such as user and
group registration files, password files, security
and integrity-level definition file, role
definition file, audit-log file shall also be
identified. It shall be possible to associate TCB
privileges with TCB operations performed by
administrative users.
2.The modules of a TCB function shall be
associated only with the privileges necessary to
complete their task.
3. Support for product privilege implementation
and association with TCB modules provided by
lower-level mechanisms or procedures (e.g.,
operating system, processors, language) shall be
provided.
ASSURANCES
Requirements for TCB Property Definition
PD-4 Formal Specification of TCB Properties
The developer shall provide formal models for the
functional components and sub-components of the
profile. At a minimum, a formal model of the
access control components shall be provided. The
properties of the formal models shall be clearly
stated. The developer shall provide a formal
interpretation of the models in the FIS of the
product's TCB. For each model entity, the
developer shall: (1) identify the TCB elements and
their FIS (if any) that implement that entity; (2)
specify the operation of these TCB elements, and
(3) prove that the FIS of these elements is
consistent with the model properties. The
developer's interpretation of each formal model,
which specifies the TCB properties, shall identify
all TCB and FIS elements (if any) that do not
correspond to any model entity and shall explain
why these elements do not render the TCB
properties invalid.
An informal model of reference mediation and TCB
protection shall be provided. For the components
that are not modeled, the developer shall
interpret the functional requirements of the
protection profile within the product TCB. For
each functional requirement, the developer shall:
(1) identify the TCB elements and their TCB
interfaces (if any) that implement that
requirement; (2) describe the operation of these
TCB elements, and (3) explain why the operation of
these elements is consistent with the functional
requirement. The developer's interpretation of
each functional requirement, which describes the
TCB properties, shall include all the TCB
elements.
Requirements for TCB Element Identification
ID-2: TCB Element Justification
The vendor shall identify the TCB elements (i.e.,
software, hardware/firmware code and data
structures). Each element must be unambiguously
identified by its name, type, release, and version
number (if any).
The developer shall justify the protection
relevance of the identified elements (i.e., only
elements that can affect the correct operation of
the protection functions shall be included in the
TCB). If protection-irrelevant elements are
included in the TCB, the developer shall provide a
rationale for such inclusion.
Requirements for TCB Interface Definition
IF-3: Formal Interface Specification
The developer shall define all external (e.g.,
command, software, and I/O) administrative (i.e.,
privileged) and non-administrative interfaces to
the TCB.
The developer shall provide and maintain a
descriptive interface specification (DIS) of the
TCB that completely and accurately describes the
TCB in terms of exceptions, error messages, and
effects. The DIS shall identify the TCB call
conventions (e.g., parameter order, call sequence
requirements), and exceptions signaled. The DIS
shall also include the TCB call identifier,
parameter types (e.g., input, output), the effect
of the call, TCB call conventions (e.g., parameter
order, call sequence requirements), and exceptions
handled and signaled. It shall be shown to be an
accurate description of the TCB interface.
A Formal Interface Specification (FIS) of the TCB
shall be maintained that accurately describes the
TCB in terms of the call identifier, parameter
types (e.g., input, output), the effect of the
call, TCB call conventions (e.g., parameter order,
call sequence requirements), and exceptions
signaled.
The DIS and FIS shall include those components of
the TCB that are implemented as hardware and/or
firmware if their properties are visible at the
TCB interface.
If the TCB consists of a kernel and privileged
processes, the developer shall separately identify
and define the interfaces for the kernel and each
privileged process.
The TCB interface definition must also include all
effects of a call including the direct visibility
and alterability of internal TCB variables and
functions.
Requirements for TCB Modular Decomposition
MD-3: Module Relationship Analysis
The developer shall design the TCB as a small
number (e.g., 10 to 100) of design and
implementation subsystems that have well-defined
functional relationships and shared-data
dependencies. The developer shall identify the
specific TCB protection properties and functions
associated with each subsystem and the TCB
interfaces (if any) implemented by each subsystem.
The developer shall design each subsystem as a set
of modules. For each module, the developer shall
describe: the role or purpose of the module, the
set of related functions performed by the module,
and the module interface (i.e., the set of
invocable functions, calling conventions,
parameters, global variables, and results). The
developer shall identify the protection functions
of, and describe the interfaces between, these
modules. The developer shall choose the modules so
that the set of functions implemented by the
module, the module's contribution to the TCB
protection properties, and the interface(s) to the
module can be described concisely (e.g., the
module shall have a single purpose). The TCB
structuring into modules shall be based on well-
defined module relationships; for example, the
contains relation (e.g., A is part of B), the
"uses" relation (e.g., A is correct only if B is
correct). The developer shall analyze the
correctness dependencies among these modules. This
analysis may include, but is not restricted to,
service and environmental dependencies.
Requirements for TCB Structuring Support
SP-3: Structured Protection Mechanisms
The TCB shall maintain process isolation. The TCB
shall separate those elements that are protection-
critical from those that are not. Features in
hardware, such as segmentation, shall be used to
support logically distinct storage objects with
separate access-control attributes (e.g.,
readable, writable). The TCB shall employ a
complete, conceptually simple, protection
mechanism with precisely defined semantics. This
mechanism shall play a central role in enforcing
the internal structuring of the TCB and the
product.
Requirements for Design Disciplines
DD-2: Extended Disciplines for TCB Structuring
The developer shall design the product to minimize
the complexity of the TCB. System engineering
shall be directed towards excluding from the TCB
modules that are not protection critical.
The TCB design shall reflect use of modern
software engineering techniques), such as data
hiding and abstraction (i.e., data, functional,
and control abstractions) and well-defined
exception-handling. The TCB design shall also
include use of layering (including a rationale for
each layering violation), high-level
synchronization constructs, and multi-tasking/
multi-threading.
Requirements for TCB Implementation Support
IM-4: Naming Support For Design Correspondence
The developer shall maintain engineering diagrams
and source code (as applicable) for all TCB
elements. The developer shall identify the
programming languages used to develop the TCB
software and reference the definitions of those
languages. The developer shall identify any
implementation dependent options of the
programming language compiler(s) used in the TCB
source code. The developer shall describe coding
standards followed during the implementation of
the product and shall ensure that all source code
complies with these standards. The diagrams and
source code for each module of the TCB shall be
identified and provided as configuration items.
The diagrams and source code shall be named using
the same conventions as those used in the TCB
design. The developer shall explain how the
programming languages used help establish the
correspondence between the TCB implementation and
design.
Requirements for Developer Functional Testing
FT-3: Specification-Driven TCB Interface Testing
The developer shall test the TCB interface to show
that all claimed protection functions work as
stated in the TCB interface description or
specification. The tests shall exercise the
boundary conditions of the protection functions.
The developer shall generate the test conditions
and data from the Descriptive Interface
Specification(s). The developer test procedures
shall include the tests used to demonstrate the
absence of all flaws discovered in previous
versions of the TCB.
The developer shall correct all flaws discovered
by testing and shall retest the TCB to show that
all discovered flaws have been eliminated, no new
flaws have been introduced, and the protection
functions work as claimed.
Requirements for Penetration Analysis
PA-2 Flaw-Hypothesis Testing
The developer shall define the TCB configuration,
interface, and protection functions that are
subject to penetration testing. For each test, the
developer shall identify the goal of the test and
the criteria for successful penetration. The
developer shall illustrate how, in addition to
system reference manuals and TCB interface
description, the DIS, source code, and hardware
and firmware specifications are used to define
penetration-test conditions. For each test, the
developer shall document all test conditions, data
(e.g., test set-up, function call parameters, and
test outcomes), and coverage.
The developer shall generate the test conditions
from flaw-hypotheses derived by negating
assertions of TCB design capabilities and by
providing counter examples that show that these
assertions are false. The developer shall confirm
the flaw hypotheses by checking design and
implementation documentation, by defining the test
data and running test programs, or by referring to
known classes of penetration flaws found in other
TCBs. The refutation of any hypothesis shall be
documented.
For each uncovered flaw, the developer shall
define and document scenarios of flaw exploitation
and shall identify all penetration outcomes
resulting from that scenario. The cause of the
flaw shall be identified and documented.
Requirements for Covert-Channel Analysis
CCA-3 Formal Covert Channel Analysis
1. Identification: The developer shall identify
all sources of information used in covert-channel
analysis. These sources shall include TCB
reference manuals, DIS, and FIS. The sources of
information and methods of identification shall
include processor specifications whenever the
identification method includes source code and
hardware analysis. The developer shall define
the identification method used. The developer
shall define the identification method used. The
developer shall demonstrate that the chosen
identification method is sound (e.g., it leads to
the discovery of all covert channels in the FIS or
source documentation) and repeatable (i.e.,
independent evaluators can use the method on the
same sources of covert-channel information and can
obtain the same results.) The method shall be
applied on the FIS of the TCB, and shall include
syntactic information-flow analysis (with or
without the use of semantic analysis) or
noninterference analysis. The identification of
covert channels shall include specification-to-
code correspondence.
The developer shall define scenarios of use for
each cover channel. The developer shall also
define timing channel scenarios, and shall
identify all functions that provide independent
sources of timing (e.g., CPUs, I/O processors).
2. Bandwidth Measurement or Engineering
Estimation: The developer shall define the method
used for covert-channel bandwidth estimation. The
method shall be based on information theory
methods. In measuring TCB performance for covert-
channel-bandwidth estimation, the developer shall
satisfy the following assumptions. The maximum
bandwidth estimation shall be based on the
assumptions that the covert channel is noiseless,
that the senders and receivers are not delayed by
the presence of other processes in the product,
and that the sender-receiver synchronization time
is negligible.
The developer shall select TCB primitives to be
measured for bandwidth determination from real
scenarios of covert channel use. The developer
shall specify TCB measurement environment for the
bandwidth measurements. This specification shall
include: (1) the speed of the product functions,
(2) the product configuration, (3) the sizes of
the memory and cache components, and (4) the
product initialization. The sensitivity of the
measurement results to configuration changes shall
be documented. The covert-channel measurements
shall include the fastest TCB function calls for
altering, viewing, and setting up the transmission
environment; the demonstrably fastest process
(context) switch time shall also be included in
the bandwidth measurements. All measurements shall
be repeatable.
3. Covert Channel Testing: The developer shall
test all the use of all identified covert channels
to determine whether the handling functions work
as intended.
Requirements for User Guidance
UG-1: Users' Guide
The developer shall provide a User Guide which
describes all protection services provided and
enforced by the TCB. The User Guide shall describe
the interaction between these services and provide
examples of their use. The User Guide may be in the
form of a summary, chapter or manual. The User
Guide shall specifically describe user
responsibilities. These shall encompass any user
responsibilities identified in the protection
profile.
Requirements for Administrative Guidance
AG-3: Role-Based Administrative Guidance
The developer shall provide a Trusted Facility
Manual intended for the product administrators and
operators that describes how to use the TCB
security services (e.g., Access Control, System
Entry, or Audit) to enforce a system security
policy. The Trusted Facility Manual shall include
the procedures for securely configuring, starting,
maintaining, and halting the TCB. The Trusted
Facility Manual shall explain how to analyze audit
data generated by the TCB to identify and document
user and administrator violations of this policy.
The Trusted Facility Manual shall explain the
unique security-relevant privileges and functions
of administrators and operators. The Trusted
Facility Manual shall also explain the distinct
security-relevant privileges and functions of the
TCB and how they can be selectively granted to
provide fine-grained, multi-person or multi-role
system and application administration policies.
The Trusted Facility Manual shall describe the
administrative interaction between security
services.
The Trusted Facility Manual shall identify all
hardware, firmware, software, and data structures
comprising the TCB. The detailed audit record
structure for each type of audit event shall be
described. The Trusted Facility Manual shall
explain how configure the product to mitigate,
eliminate, or audit their exploitation. The
Trusted Facility Manual shall describe the
cautions about and procedures for using the TCB as
a base for site-specific secure applications. The
Trusted Facility Manual shall describe procedures
for securely regenerating the TCB after any part
is changed (e.g., due to adding devices or
installing flaw corrections to the TCB software).
The Trusted Facility Manual shall be distinct from
User Guidance, and encompass any administrative
responsibilities identified in security
management.
Requirements for Trusted Generation
TG-3: Trusted Generation With Secure State Review
The developer shall establish and document the
procedures that a consumer must perform to
generate an operational TCB from the delivered
copy of the master TCB. The consumer documentation
shall identify any system parameters, which are
initialized or set during system generation, that
affect the TCB's conformance to the protection
profile and state the acceptable ranges of values
for those parameters. The product shall be
delivered with each of these parameters set to its
fail-safe defaults. The developer shall provide
the consumer with a capability to review the
product security state (e.g., by providing a
program, which could be executed after generating
and starting the TCB, that determines the
consistency of the protection-relevant
parameters).
Requirements for Life Cycle Definition
LC-3: Measurable Life Cycle Process
The developer shall develop and maintain the
product using a well defined, standardized, and
measurable engineering process. The developer
shall explain why the process was chosen and how
the developer uses it to develop and maintain the
product. The developer shall comply with the
engineering process standard. The process shall
incorporate a security policy that states the
technical, physical, procedural, personnel, and
other measures used by the developer to protect
the product and its documentation. The developer
shall demonstrate that each development process
and support process requirement of the protection
profile is satisfied by some part, or parts, of
the developer's process. The developer shall
identify the programming languages used to develop
the TCB software and reference the definitions of
those languages. The developer shall identify any
implementation dependent options of the
programming language compiler(s) used to implement
the TCB software and reference the definitions of
those languages.The developer shall describe
coding standards followed during the
implementation of the product and shall ensure
that all source code complies with these
standards.
Requirements for Configuration Management
CM-4: Extended Configuration Management
The developer shall establish configuration
control and generation procedures employing
automated tools for developing and maintaining the
TCB. The procedures shall be employed to ensure
that all changes to the TCB are consistent with
the product's protection properties and security
policy. The developer shall employ these tools to
track and control changes to development evidence,
implementation data (e.g., source code and
hardware diagrams), executable versions of the
TCB, test documentation and procedures, identified
flaws, and consumer documentation. The procedures
shall include a formal acceptance process for
protection-relevant changes.
The configuration control procedures shall assure
a consistent mapping among documentation and code
associated with the current version of the TCB and
permit the regeneration of any supported version
of the TCB. The developer shall provide tools for
the generation of a new version of the TCB from
source code. Also, tools shall be available for
comparing a newly generated version with the
previous TCB version to ascertain that only the
intended changes have been made in the code that
will actually be used as the new version of the
TCB. The developer shall use a combination of
technical, physical, and procedural safeguards to
protect the master copy or copies of all material
used to generate the TCB from unauthorized
modification or destruction.
Requirements for Trusted Distribution
TD-1: TCB Modification Detection During Distribution
The developer shall establish procedures and
employ appropriate technical measures to detect
modifications to any TCB-related software,
firmware, and hardware, including updates, that is
transferred from the development environment to a
consumer's site.
Requirements for Evidence of TCB Protection Properties
EPP-4 Evidence of Formal Model Interpretation in the FIS
The developer shall provide documentation which
describes the correspondence between the
functional component requirements and the TCB
elements and interfaces. This documentation shall
describe how the TCB implements the reference
monitor concept. The developer shall also provide
a formal access-control model and an informal
reference mediation and TCB protection model. The
TCB properties, which are defined by this
correspondence and the interpretation of these
models within the DIS and FIS of the TCB shall be
documented by the product developer.
Requirements for Evidence of Product Development
EPD-5: Policy Consistency Of The FIS
The developer shall provide a Descriptive
Interface Specification (DIS) that describes the
functions, effects, exceptions and error messages
visible at the TCB interface and includes a
convincing argument that the DIS is consistent
with the formal model of the policy. The developer
shall show that the DIS is an accurate
representation of the TCB's external interfaces.
The developer shall provide a Formal Interface
Specification (FIS) that rigorously defines the
protection functions available at the TCB
interface in terms of: the protection properties
implemented by each function, the precise
semantics for invoking each function, the effects
of each function (i.e., returned values and effect
on the TCB state), and the possible exceptions and
error messages returned by each function. The FIS
shall be accompanied by a convincing argument that
it is consistent with the formal model of the
product protection policy. This argument shall be
constructed using both manual and machine-assisted
specification and verification methods. Machine-
assisted specification and verification methods
shall be approved by the product evaluation
authority.
The developer shall provide TCB Design
Specifications that include: a list of the TCB
elements (hardware, software, and firmware
configuration items); a list of protection
services provided to the TCB by hardware,
software, and firmware that is not part of the
TCB; an explanation of the techniques and criteria
used during the modular decomposition of the TCB;
a description of the policy allocations,
functions, and interactions among the major TCB
subsystems; module level descriptions of all
software and hardware in the TCB; and an argument
that the design implements exactly the functions
specified in the FIS.
The developer shall provide TCB Implementation
Data consisting of the engineering diagrams for
all hardware included in the TCB and the source
code used to generate the TCB software and
firmware. The developer shall show, through either
manual or machine-assisted correspondence methods,
that the TCB software, firmware, and hardware
implement the documented TCB design.
Requirements for Evidence of Functional Testing
EFT-3: Evidence of Specification-Driven Testing
The developer shall provide evidence of the
functional testing that includes the test plan,
the test procedures, and the results of the
functional testing. The test, plans, procedures,
and results shall be maintained under the same
configuration control as the TCB software. The
test plans shall identify the TCB specification
used in the derivation of the test conditions,
data, and coverage analysis.
Requirements for Evidence of Penetration Analysis
EPA-2: Evidence of Flaw-Hypothesis Generation and Testing
The developer shall provide evidence of
penetration testing. The penetration evidence
shall identify all product documentation and
development evidence on which the search for flaws
was based. The penetration evidence shall describe
the scenarios for exploiting each potential flaw
in the system and the penetration test conditions,
data (e.g., test set-up, function call parameters,
and test outcomes), coverage, and conclusions
derived from each scenario. The penetration
evidence shall summarize both refuted and
confirmed flaws hypothesis.
Requirements for Evidence of Covert Channel Analysis
ECC-2: Evidence of Covert Channel Analysis and Handling
The developer's documentation shall present the
results of the covert channel analysis and the
trade-offs involved in restricting these channels.
All auditable events that may be used in the
exploitation of known covert channels shall be
identified. The developer shall provide the
bandwidths of known covert channels whose use is
not detectable by the auditing mechanism. The
documentation of each identified covert channel
shall consist of the variables, timing sources,
and the TCB interface functions that can be used
to transmit information. The measurements of each
TCB function call used by covert channels must be
documented and the bandwidth computation shall be
included for each channel. The measurement
environment should be documented as specified.
Test documentation shall include results of
testing the effectiveness of the methods used to
reduce covert-channel bandwidths.
Requirements for Evidence of Product Support
EPS-3: Evidence of Measured Product Support
The developer shall provide documentation that
defines, explains, and justifies the policies,
procedures, plans, and tools established by the
developer to satisfy the Operational Support and
Development Environment requirements of the
protection profile. The documentation shall also
explain how the developer periodically evaluates
compliance with the established procedures,
policies, and plans.
Requirements for Test Analysis
TA-5: Formal Test Analysis
The evaluator shall assess whether the producer
has performed the activities defined in the
development assurance requirements of the
protection profile for functional testing and
penetration analysis, and whether the producer has
documented these activities as defined in the
development evidence requirements of the
protection profile. The evaluator shall analyze
the results of the producer's testing activities
for completeness of coverage and consistency of
results, and general correctness (e.g., defect
trend from regression testing). This analysis
shall examine the testability of requirements, use
of the FIS for test derivation, the adequacy of
the tests to measure the required properties, the
deviation of the actual results obtained from the
expected results. The analysis shall extend to
trace all defects identified, corrected, and
retested. The analysis shall include an assessment
of test coverage and completeness, and defect
frequency. The results of testing shall be
interpreted in terms that express product
performance and protection adequacy. The evaluator
shall determine whether the product's protection
properties, as defined for the entire TCB, and all
relevant known penetration flaws have been tested.
The evaluator shall independently develop, test,
and document additional flaw hypotheses. The
evaluator shall assess testing results to
determine whether the product's TCB works as
claimed, that the TCB's implementation is
consistent with the FIS, and whether there are any
obvious ways (i.e., ways that are known, or that
are readily apparent or easily discovered in
product documentation) for an unauthorized user to
bypass the policy implemented by the TCB or
otherwise defeat the product's TCB, and whether
all discovered TCB flaws have been corrected and
no new TCB flaws introduced. No design flaws and
no more than a few correctable implementation
flaws may be found during testing and there shall
be reasonable confidence that few remain. If
covert channel handling methods have been
implemented, the testing results shall show that
the methods used to reduce covert channel
bandwidths have been effective for all evaluated
configurations. The evaluator shall determine
whether the product is completely resistant to
penetrations.
IT-4: Formal Independent Testing.
The evaluator shall independently perform
functional and elementary penetration testing to
confirm test results. This testing shall be based
on (1) the results of producer or other
independent testing, (2) the TCB's FIS, (3) the
product's design and implementation documentation,
(4) the product's user and administrative
documentation, (5) relevant known penetration
flaws, and (6) evaluator-developed TCB penetration
flaw hypotheses and corresponding tests that
attempt to exploit the hypothesized flaws.
Satisfactory completion consists of demonstrating
that all TCB functions work as described in the
product's relevant documentation, that the TCB
functions are consistent with the FIS, that test
results are consistent, and that no discrepancies
exist between the documentation and the product.
Satisfactory penetration test completion shall be
determined by the subjective judgement of the
evaluator (which may be supported
algorithmically). Test duration agreements may
further constrain this judgement. Categorization
of an actual penetration flaw shall be based on
the reproducibility of that flaw. Flaws that are
discovered, but are not reproducible shall remain
categorized as potential penetration flaws. All
actual penetration flaws must be corrected and
retested.
The evaluator shall provide a penetration test
plan document that describes the additional
evaluator-developed flaw hypotheses and associated
tests. The evaluator shall execute these tests and
shall report any discovered flaws to the producer
as part of the testing results. At the conclusion
of penetration testing, the evaluator shall
provide copies of this penetration test plan and
its test results to the producer. The producer
shall ensure that this test plan and its test
results are incorporated into the rest of the
product's testing documentation and that such
documentation is available for further analysis
throughout the life of the product.
The evaluator shall test for covert channel
bandwidth reductions to determine the
effectiveness of handling method(s) in reducing
the bandwidths of identified covert channels.
Requirements for Development Environment
DER-3: Comprehensive Development Environment Review
The evaluator shall review the producer's
development and maintenance process description
documentation and shall conduct a complete audit
of the producer's processes using the evidence
generated by each process to determine the degree
of discipline enforced upon and within the
process, and to determine the protection
characteristics associated with the product's
development and maintenance. The results of this
review shall establish, for the evaluator, the
producer's development environment, its policies,
and the degree of enforcement maintained during
development execution. The review shall also
confirm the producer's complete conformance with
all relevant development environment requirements.
Requirements for Operational Support
OSR-3 Comprehensive Operational Support Review
The evaluator shall review all documentation
focused on the activities of product use (e.g.,
Users Manuals) and product administration
including installation, operation, maintenance,
and trusted recovery (e.g., Trusted Facility
Management manuals. This review shall assess the
clarity of presentation, difficulty in locating
topics of interest, ease of understanding, and
completeness of coverage. The need for separate
manuals dedicated to protection-relevant aspects
of the product should be assessed for
effectiveness. The evaluator shall execute all
documented protection-relevant features and
procedures to determine if their descriptions are
accurate and correct.
Requirements for Design Analysis
DA-3: Comprehensive Design Analysis
The evaluator shall determine whether the producer
has performed the activities defined in the
development process assurance requirements of the
protection profile for TCB property definition and
TCB design. The evaluator shall determine whether
the producer has documented these activities as
defined in the development evidence requirements
of the protection profile. The evaluator shall
analyze, with the help of formal methods and
appropriate automated tools, the results of the
producer's activities for completeness,
consistency, and correctness of design with
respect to requirements (e.g., validating the
formal verification of the design).
Requirements for Implementation
CI-3: Comprehensive Implementation Analysis
The evaluator shall conduct an inspection on a
moderate sample of randomly selected product code.
The assessment shall focus on the clarity of the
coding style, adherence to coding standards,
coding documentation, and on possible software
defects that may be present with respect to the
product's formal design and model. The inspection
shall be performed to obtain only a sample of
possible software defects, not to capture all such
possible defects. The evaluator shall report all
discovered defects to the producer; the assessment
shall report the number of defects found per line
of code inspected from the random sample size. Use
of producer-provided code inspection results can
supplement this inspection. All trapdoors built
into the product for maintenance purposes shall be
identified by the producer and shown to be
protected by the product. The producer shall
correct all discovered defects and the corrected
software reinspected. A rigorous analysis of the
implementation's correspondence to the verified
design shall be performed by the evaluator to
validate correctness. Such analysis may be
supported by appropriate automated tools.
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