Software Defined Radio Hack Chat

Join us on Wednesday, September 18 at noon Pacific for the Software Defined Radio Hack Chat with Corrosive!

If you’ve been into hobby electronics for even a short time, chances are you’ve got at least one software-defined radio lying around. From the cheap dongles originally intended to watch digital TV on a laptop to the purpose-built transmit-capable radio playgrounds like HackRF, SDR has opened up tons of RF experimentation. Before SDR, every change of band or mode would need new hardware; today, spinning up a new project is as simple as dragging and dropping a few blocks around on a screen, and SDRs that can monitor huge swaths of radio spectrum for the tiniest signal have been a boon to reverse engineers everywhere.

Corrosive is the handle of Harold Giddings, amateur callsign KR0SIV, and he’s gotten into SDR in a big way. Between his blog, his YouTube channel, and his podcast, all flying under the Signals Everywhere banner, he’s got the SDR community covered. Whether it’s satellite communications, aircraft tracking, amateur radio, or even listening in on railway operations, Harold has tried it all, and has a wealth of SDR wisdom to share. Join us as we discuss the state of the SDR ecosystem, which SDR to buy for your application, and even how to transmit with an SDR (hint: you’ll probably want a ham license.)

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, September 18 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Alarm System Defeated By $2 Wireless Dongle, Nobody Surprised

It seems a bit unfair to pile on a product that has already been roundly criticized for its security vulnerabilities. But when that product is a device that is ostensibly deployed to keep one’s family and belongings safe, it’s plenty fair. And when that device is an alarm system that can be defeated by a two-dollar wireless remote, it’s practically a responsibility.

The item in question is the SimpliSafe alarm system, a fully wireless, install-it-yourself system available online and from various big-box retailers. We’ve covered the system’s deeply flawed security model before, whereby SDRs can be used to execute a low-effort replay attack. As simple as that exploit is, it looks positively elegant next to [LockPickingLawyer]’s brute-force attack, which uses a $2 RF remote as a jammer for the 433-MHz wireless signal between sensors and the base unit.

With the remote in close proximity to the system, he demonstrates how easy it would be to open a door or window and enter a property guarded by SimpliSafe without leaving a trace. Yes, a little remote probably won’t jam the system from a distance, but a cheap programmable dual-band transceiver like those offered by Baofeng would certainly do the trick. Not being a licensed amateur operator, [LockPickingLawyer] didn’t test this, but we doubt thieves would have the respect for the law that an officer of the court does.

The bottom line with alarm systems is that you get what you pay for, or sadly, significantly less. Hats off to [LockPickingLawyer] for demonstrating this vulnerability, and for his many other lockpicking videos, which are well worth watching.

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Remote ADS-B Install Listens In On All The Aircraft Transmissions With RTL-SDR Trio, Phones Home On Cellular

When installing almost any kind of radio gear, the three factors that matter most are the same as in real estate: location, location, location. An unobstructed location at the highest possible elevation gives the antenna the furthest radio horizon as well as the biggest bang for the installation buck. But remote installations create problems, too, particularly with maintenance, which can be a chore.

So when [tsimota] got a chance to relocate one of his Automatic Dependent Surveillance-Broadcast (ADS-B) receivers to a remote site, he made sure the remote gear was as bulletproof as possible. In a detailed write up with a ton of pictures, [tsimota] shows the impressive amount of effort he put into the build.

The system has a Raspberry Pi 3 with solid-state drive running the ADS-B software, a powered USB hub for three separate RTL-SDR dongles for various aircraft monitoring channels, a remote FlightAware dongle to monitor ADS-B, and both internal and external temperature sensors. Everything is snuggled into a weatherproof case that has filtered ventilation fans to keep things cool, and even sports a magnetic reed tamper switch to let him know if the box is opened. An LTE modem pipes the data back to the Inter, a GSM-controlled outlet allows remote reboots, and a UPS keeps the whole thing running if the power blips atop the 15-m building the system now lives on.

Nobody appreciates a quality remote installation as much as we do, and this is a great example of doing it right. Our only quibble would be the use of a breadboard for the sensors, but in a low-vibration location, it should work fine. If you’ve got the itch to build an ADS-B ground station but don’t want to jump in with both feet quite yet, this beginner’s guide from a few years back is a great place to start.

Non-Nefarious Raspberry Pi Only Looks Like A Hack

We’re going to warn you right up front that this is not a hack. Or at least that’s how it turned out after [LiveOverflow] did some digital forensics on a mysterious device found lurking in a college library. The path he took to come to the conclusion that nothing untoward was going on was interesting and informative, though, as is the ultimate purpose of the unknown artifacts.

As [LiveOverflow] tells us in the video below, he came upon a Reddit thread – of which we can now find no trace – describing a bunch of odd-looking devices stashed behind garbage cans, vending machines, and desks in a college library. [LiveOverflow] recognized the posted pictures as Raspberry Pi Zeroes with USB WiFi dongles attached; curiosity piqued, he reached out to the OP and offered to help solve the mystery.

The video below tells the tale of the forensic fun that ensued, including some questionable practices like sticking the device’s SD card into the finder’s PC. What looked very “hackerish” to the finder turned out to be quite innocuous after [LiveOverflow] went down a remote-diagnosis rabbit hole to discern the purpose of these devices. We won’t spoil the reveal, but suffice it to say they’re part of a pretty clever system with an entirely non-nefarious purpose.

We thought this was a fun infosec romp, and instructive on a couple of levels, not least of which is keeping in mind how “civilians” might see gear like this in the wild. Hardware and software that we deal with every day might look threatening to the general public. Maybe the university should spring for some labels describing the gear next time.

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Classifying Crystals With An SDR Dongle

When it comes to radio frequency oscillators, crystal controlled is the way to go when you want frequency precision. But not every slab of quartz in a tiny silver case is created equal, so crystals need to be characterized before using them. That’s generally a job for an oscilloscope, but if you’re clever, an SDR dongle can make a dandy crystal checker too.

The back story on [OM0ET]’s little hack is interesting, and one we hope to follow up on. The Slovakian ham is building what looks to be a pretty sophisticated homebrew single-sideband transceiver for the HF bands. Needed for such a rig are good intermediate frequency (IF) filters, which require matched sets of crystals. He wanted a quick and easy way to go through his collection of crystals and get a precise reading of the resonant frequency, so he turned to his cheap little RTL-SDR dongle. Plugged into a PC with SDRSharp running, the dongle’s antenna input is connected to the output of a simple one-transistor crystal oscillator. No schematics are given, but a look at the layout in the video below suggests it’s just a Colpitts oscillator. With the crystal under test plugged in, the oscillator produces a huge spike on the SDRSharp spectrum analyzer display, and [OM0ET] can quickly determine the center frequency. We’d suggest an attenuator to change the clipped plateau into a sharper peak, but other than that it worked like a charm, and he even found a few dud crystals with it.

Fascinated by the electromechanics of quartz crystals? We are too, which is why [Jenny]’s crystal oscillator primer is a good first stop for the curious.

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DRM Workarounds Save Arcade Cabinet

DRM has become a four-letter word of late, with even media companies themselves abandoning the practice because of how ineffective it was. DRM wasn’t invented in the early 2000s for music, though. It’s been a practice on virtually everything where software is involved, including arcade cabinets. This is a problem for people who restore arcade machines, and [mon] has taken a swing at unraveling the DRM for a specific type of Konami cabinet.

The game in question, Reflec Beat, is a rhythm-based game released in 2010, and the security is pretty modern. Since the game comes with a HDD, a replacement drive can be ordered with a security dongle which acts to decrypt some of the contents on the HDD, including the game file and some other information. It’s not over yet, though. [mon] still needs to fuss with Windows DLL files and a few levels of decryption and filename obfuscation before getting the cabinet functional again.

The writeup on this cabinet is very detailed, and if you’re used to restoring older games, it’s a bit of a different animal to deal with than the embedded hardware security that older cabinets typically have. If you’ve ever wanted to own one of these more modern games, or you’re interested in security, be sure to check out the documentation on the project page. If your tastes are more Capcom and less Konami, check out an article on their security system in general, or in de-suiciding boards with failing backup batteries.

A TEMPEST In A Dongle

If a couple of generations of spy movies have taught us anything, it’s that secret agents get the best toys. And although it may not be as cool as a radar-equipped Aston Martin or a wire-flying rig for impossible vault heists, this DIY TEMPEST system lets you snoop on computers using secondary RF emissions.

If the term TEMPEST sounds familiar, it’s because we’ve covered it before. [Elliot Williams] gave an introduction to the many modalities that fall under the TEMPEST umbrella, the US National Security Agency’s catch-all codename for bridging air gaps by monitoring the unintended RF, light, or even audio emissions of computers. And more recently, [Brian Benchoff] discussed a TEMPEST hack that avoided the need for thousands of dollars of RF gear, reducing the rig down to an SDR dongle and a simple antenna. There’s even an app for that now: TempestSDR, a multiplatform Java app that lets you screen scrape a monitor based on its RF signature. Trouble is, getting the app running on Windows machines has been a challenge, but RTL-SDR.com reader [flatfishfly] solved some of the major problems and kindly shared the magic. The video below shows TempestSDR results; it’s clear that high-contrast images at easiest to snoop on, but it shows that a $20 dongle and some open-source software can bridge an air gap. Makes you wonder what’s possible with deeper pockets.

RF sniffing is only one of many ways to exfiltrate data from an air-gapped system. From power cords to security cameras, there seems to be no end to the ways to breach systems.

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