💾 Archived View for clemat.is › saccophore › library › shorts › defcon › 24 › DEFCON-24-Gtwgn-Untitl… captured on 2021-12-03 at 14:04:38.
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The steady beat of one of my favorite songs is thumping in the background. Eighties hair metal. Not exactly Bang Your Head, but, it's in that genre. I recite the lyrics unconsciously while thinking of something else entirely. I am finally getting some work done. I'm in my zone. Bing! Coffee is now spilling on my desk. After I head off the stream from dousing my power strip and get my desk mostly cleaned up, I look for my phone. Muttering curses under my breath, I find it. I really need to change that ringtone. It is a concentration shatterer. Huh, John sent that text. He usually doesn't bug me when I'm working. The text reads, "Bob I need your help, it's for Sue". Sigh. I hope this really is important. So, I tap the little phone icon near his name on my screen. "Dude, what's up?" I said. "Bob! Thanks for getting back with me. I know you're trying to pay bills and whatnot," he drops off. "It's Sue, I'm worried about her. You know that jerk of a boyfriend I told you about? Well, he threatened her, and Sue got a restraining order against him. He hasn't come back by her place and knocked. He hasn't called her. But, she has seen his car drive in front of her place three times today, and that's just the times she noticed. She's the only sister I got, I need to help her out somehow without doing it overtly pushing this guy over the edge. He's a loose cannon. Do you have anything in your bag of tricks that can track him, so she'll know if he is stalking her?" "Wow. That's pretty crappy. I don't know right now. I can think about it. I can't just put a gps tracker on his vehicle. Even cops aren't supposed to do that without a warrant. If I did that and you tried use that as evidence, we'd both be worse than he is currently. Let me get back with you." Actually, I have an idea, but I don't want to get his hopes up. "Thanks, man, I know you're busy. I really appreciate it." There is a project that might work for this. Where did I put it? Oh, yeah, in that bin above that old Pace soldering station. A few days later I find myself over at Sue's place, knocking on the front door. I see the living room curtain shift a little. Then I hear, "Who is it?" She doesn't sound like she is running scared, but I do hear some tension in her voice. "My name is Bob. Your brother, John, asked me if I could help you with an issue. I have something for you." I step back so she can clearly see me from the door's peephole. I hear a chain move, a deadbolt click, and the door opens. "Thank you. John said you might be coming over today. Would you like to come in?" She offered. "No need. This won't take long." I pull a project box out of my jacket pocket, and the wall wart that powers it. "Here you go. Plug this in and set the box by the window. Every time you see your ex's car drive by, press this button for as long as you see the vehicle. If he is just sitting there, please note his arrival time and departure time as best you can and give that info to me later when I return. After you have seen his car and pressed the button on about five occasions, call John. After that, I'll come get the box and we'll go from there. I'm sorry if this isn't a super quick solution, but it should work." "Thank you so much", she says, as I hand her my little black box that's about the size of two waffles stacked together. Two days later I get a text message from John, letting me know it's time to retrieve my little data vacuum from Sue. Since this is my first field test of the device, I don't know much data it will have stored. It's probably more than I want to pay for using a GSM add-on and a new plan. I'll just get my data off of the 32Gb microSD card installed inside. I drop by her place to pick up my device. "Well, that was quick. He just keeps driving by in defiance of the order?" "Yes, he's a creep. He didn't act like that at first. Here's your box. How is this going to help me?" "This box is a prototype. If it worked as I planned, and the data is usable, I'll be able to know whenever his phone is near you. We should be able to work with that. I'll take this back to my office. If everything goes roughly as I hope, I'll be back tomorrow with the box for the next step." "Thank you again", she says as she closes the door and sets her various locks. Well, would you look at that. I look through the data and the pattern that I had hoped for did, indeed, appear. That nifty little gadget of mine is actually a combination of gadgets. It's a Raspberry Pi, an FPGA add-on board, and software defined radio. While it's plugged in, the SDR is always listening to the GSM band in its immediate vicinity. When the button is pressed it data logs every IMEI that is transmitting to any nearby cell tower, and the strength of those transmissions. The FPGA handles the bandwidth for all that traffic, the rpi saves it to the SD for me. During every instance of Sue pressing that button there were cell signals that were stationary. These are people in nearby residences or businesses. They are filtered out of my search. Then, I found the one cell signal that varied in strength, because it was moving towards or away from a cell tower, that was present every time Sue pressed that button. That one common signal contains the IMEI of the perp. This is pretty useful since an IMEI is like a MAC address for a cell phone. Now to test the next phase. I reprogram my little device so that it is still always listening, but now it is specifically looking for the IMEI of the crazy ex's phone. It still records like a barebones stingray when the ex is near. What's new is that I add another device to the kit, an HD webcam. Whenever the ex drives by, the box triggers the webcam to record. Without a more permanent installation, this will only work during the day because the webcam is inside the house. When the infrared LEDs turn on when it's dark outside, they reflect off of the living room window and bloom out the video. That being said, it should still get the work done. I return the box to Sue. This time I do go inside to setup the camera to make sure its focus is on the road and not twenty feet in front of it. After all that, I ask her to just let it do its thing for a while, and if things escalate to call the police without hesitating. I'm guessing that nothing went farther than just stalking because I didn't hear anything more when I retrieved my gear the following week from Sue's place. The jerk is still breaking the protective order by driving by her place, which is particularly out of the way from his own house and job. Hmm, he thinks no one will notice. For now, I'm keeping the cell data to myself. I'm good, no issues with that I'm sure, because I was only passively listening. Even though I was helping a big brother, I am not Big Brother, so, no laws broken. If you are going to freely transmit your data in close proximity to me, I'm also free to listen and log. What I did provide was a dvd with time stamped video of the ex driving by Sue's place seven times within one week, and twice in a van that belongs to one of his friends who is known to both Sue and John. After providing that dvd to Sue's lawyer, and after that to the presiding judge, the jerk was rounded up to stand before the same judge for breaking the protective order. He got to spend sometime behind bars to make a point. It seems the point was taken to heart, at least for now. Sue has not seen him anywhere her place for at least a week now. I'm sitting at my desk working on projects for clients. This time I'm listening to nineties grunge. My phone rings and I see that it's John. Happy that I didn't spill my coffee, I answer the call. "Hey, how goes?" "I called to say thanks for helping my sister. That dvd was really helpful. Thanks, it means a lot. Oh, am I interrupting one of those seminars? Aren't you at DEFCON?" "No, that's next week." "Oh, okay. Hey, umm, I'm curious, how did you know when Sue's crazy ex was driving by? How did you do that?" "Yeah, that", I grimace. "You know those smartphones that we all carry around nowadays?" "What about them?" "Well, not only are they convenient for communication and entertainment, they are also like chains or, better yet, beacons that tell anyone and everyone where we are if only we have the right gear to see that beacon. I've been thinking about it more recently. Everything is connected. It's kinda like one of those rise of the machines movies. It ain't skynet, but it is AT&T, Verizon, NSA and all that. If your phone is on, there is a global system that knows exactly where you are, and it's by design. If it wasn't, it couldn't route calls. But, that doesn't make it less creepy. Anyway, he was advertising everywhere he went and didn't even know it. I did a little data mining and picked him out of a crowd." I chuckle. "John, you are in the matrix."