signal analysis

3 Articles

Identifying Malware By Sniffing Its EM Signature

January 19, 2022 by 17 Comments

The phrase “extraordinary claims require extraordinary evidence” is most often attributed to Carl Sagan, specifically from his television series Cosmos. Sagan was probably not the first person to put forward such a hypothesis, and the show certainly didn’t claim he was. But that’s the power of TV for you; the term has since come to be known as the “Sagan Standard” and is a handy aphorism that nicely encapsulates the importance of skepticism and critical thinking when dealing with unproven theories.

It also happens to be the first phrase that came to mind when we heard about Obfuscation Revealed: Leveraging Electromagnetic Signals for Obfuscated Malware Classification, a paper presented during the 2021 Annual Computer Security Applications Conference (ACSAC). As described in the mainstream press, the paper detailed a method by which researchers were able to detect viruses and malware running on an Internet of Things (IoT) device simply by listening to the electromagnetic waves being emanated from it. One needed only to pass a probe over a troubled gadget, and the technique could identify what ailed it with near 100% accuracy.

Those certainly sound like extraordinary claims to us. But what about the evidence? Well, it turns out that digging a bit deeper into the story uncovered plenty of it. Not only has the paper been made available for free thanks to the sponsors of the ACSAC, but the team behind it has released all of code and documentation necessary to recreate their findings on GitHub.

Unfortunately we seem to have temporarily misplaced the $10,000 1 GHz Picoscope 6407 USB oscilloscope that their software is written to support, so we’re unable to recreate the experiment in full. If you happen to come across it, please drop us a line. But in the meantime we can still walk through the process and try to separate fact from fiction in classic Sagan style.

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Exposing Computer Monitor Side-Channel Vulnerabilities With TempestSDR

July 15, 2020 by 12 Comments

Having been endlessly regaled with tales of side-channel attacks and remote exploits, most of us by now realize that almost every piece of gear leaks data like a sieve. Everything from routers to TVs to the power supplies and cooling fans of computers can be made to give up their secrets. It’s scary stuff, but it also sounds like a heck of a lot of fun, and with an SDR and a little software, you too can get in on the side-channel action.

Coming to us via software-defined radio buff [Tech Minds], the video below gives a quick tour of how to snoop in on what’s being displayed on a monitor for almost no effort or expense. The software that makes it possible is TempestSDR, which was designed specifically for the job. With nothing but an AirSpy Mini and a rubber duck antenna, [Tech Minds] was able to reconstruct a readable black and white image of his screen at a range of a few inches; a better antenna and some fiddling might improve that range to several meters. He also shares a trick for getting TempestSDR set up for all the popular SDRs, including SPRplay, HackRF, and RTL-SDR.

Learning what’s possible with side-channel attacks is the key to avoiding them, so hats off to [Tech Minds] for putting together this simple, easy-to-replicate demo. To learn even more, listen to what [Samy Kamkar] has to say about the subject, or check out where power supplies, cryptocurrency wallets, and mixed-signal microcontrollers are all vulnerable.

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Safe Cracking With Signal Analysis

July 13, 2015 by 46 Comments

[Dave Jones] over at EEVblog got his hands on a small safe with an electronic lock and decided to try his hand at safe cracking. But rather than breaking out the thermal drill or shaped charge, he hooked up his Rigol scope and attempted a safe cracking via signal analysis (YouTube link).

We have to say that safes Down Under seem much stouter than most of the inexpensive lock boxes we’ve seen in the US, at least in terms of the quality (and quantity) of the steel in the body of the safe. Even though [Dave] was looking for a way in through the electronics, he still needed to deal with all that steel to get himself out of a face-palm moment that resulted in a lockout. Once that was out of the way, he proceeded to capture usable signals from the internal microcontroller using the only two available contacts – the 9 volt battery connections. While he did get signals, he couldn’t find any signatures that would help determine the six digits in the PIN, and as he points out, even if he did, brute-forcing through the one million permutations to find the right code would take too long, given the wrong-code lockout feature of the lock.

Even though he failed to hack into this particular safe, there’s still plenty to be learned from his methods. And who’s to say that other similar locks aren’t a little more chatty about their internals? Maybe you could even manage to EMP your way past the lock.