Build Your Own GSM Base Station For Fun And Profit

Over the last few years, news that police, military, and intelligence organizations use portable cellular phone surveillance devices – colloquially known as the ‘Stingray’ – has gotten out, despite their best efforts to keep a lid on the practice. There are legitimate privacy and legal concerns, but there’s also some fun tech in mobile cell-phone stations.

Off-the-shelf Stingray devices cost somewhere between $16,000 and $125,000, far too rich for a poor hacker’s pocketbook. Of course, what the government can do for $100,000, anyone else can do for five hundred. Here’s how you build your own Stingray using off the shelf hardware.

[Simone] has been playing around with a brand new BladeRF x40, a USB 3.0 software defined radio that operates in full duplex. It costs $420. This, combined with two rubber duck antennas, a Raspberry Pi 3, and a USB power bank is all the hardware you need. Software is a little trickier, but [Simone] has all the instructions.

Of course, if you want to look at the less legitimate applications of this hardware, [Simone]’s build is only good at receiving/tapping/intercepting unencrypted GSM signals. It’s great if you want to set up a few base stations at Burning Man and hand out SIM cards like ecstasy, but GSM has encryption. You won’t be able to decrypt every GSM signal this system can see without a little bit of work.

Luckily, GSM is horribly, horribly broken. At CCCamp in 2007, [Steve Schear] and [David Hulton] started building a rainbow table of the A5 cyphers that is used on a GSM network between the handset and tower. GSM cracking is open source, and there are flaws in GPRS, the method GSM networks use to relay data transmissions to handsets. In case you haven’t noticed, GSM is completely broken.

Thanks [Justin] for the tip.

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Hackaday Links: January 11, 2015

Listening tests reveal significant sound quality differences between various digital music storage technologies. Finally the audiophile press is tackling the important questions. This listening test looks at the difference between two four-bay NAS boxes, with one making the piano on Scherzo and Trio from Penguin Café Orchestra’s Union Cafe sound more Steinway-like, while another NAS makes it sound more like a Bosendörfer. Yes, your choice of digital storage medium can change the timbre of a piano. Another gem: “Additionally, the two units also had different processor architectures, which might also affect perceived audible differences.” There must be a corollary to Poe’s Law when it comes to audiophiles…

[10p6] has begun a project that can play every old Atari cartridge. Right now it’s just a few bits of plastic that fits every non-Jaguar Atari cartridge, but it’s a start.

The Android IMSI-Catcher Detector. You’ve heard about Stingrays, devices used by law enforcement that are basically fake cell towers. These Stingrays downgrade or disable the encryption present in all cellphones, allowing anyone, with or without a warrant, to listen in on any cell phone conversation. Now there’s an effort to detect these Stingrays. It’s open source, and they’re looking for volunteers.

[Rob] sent in something that’s the perfect application of projection mapping. It’s called Face Hacking, and it’s pretty much just a motion capture systems, a few projectors, a whole lot of CG work, and just a tiny bit of dubstep. It look cool, but we’re wondering what the applications would be. Theatre or some sort of performance art is the best I can come up with.

A while ago, [4ndreas] saw a 3D printed industrial robot arm. He contacted the guy for the files, but nothing came of that. [4ndreas] did what anyone should do – made his own 3D printable industrial robot arm. The main motors are NEMA 17, and printing this will take a long time. Still, it looks really, really cool.

graphic of man with cellphone linking to cell tower

Ask Hackaday: Stopping The Stingray

There’s pandemonium on the streets. You look down from your 4 story apartment and see hundreds of people marching and chanting. You pick up your phone and call your buddy, expecting it to link up to the nearest cell tower which will route your call to where it needs to go. Instead, without your knowledge, you link to a tricked-out police surveillance truck a few blocks away. They intercept your call and listen to the conversation in hopes of tracking the protest.

Continue reading “Ask Hackaday: Stopping The Stingray”