What’s in your crypto wallet? The simple answer should be fat stacks of Bitcoin or Ethereum and little more. But if you use a hardware cryptocurrency wallet, you may be carrying around a bit fat vulnerability, too.
At the 35C3 conference last year, [Thomas Roth], [Josh Datko], and [Dmitry Nedospasov] presented a side-channel attack on a hardware crypto wallet. The wallet in question is a Ledger Blue, a smartphone-sized device which seems to be discontinued by the manufacturer but is still available in the secondary market. The wallet sports a touch-screen interface for managing your crypto empire, and therein lies the weakness that these researchers exploited.
By using a HackRF SDR and a simple whip antenna, they found that the wallet radiated a distinctive and relatively strong signal at 169 MHz every time a virtual key was pressed to enter a PIN. Each burst started with a distinctive 11-bit data pattern; with the help of a logic analyzer, they determined that each packet contained the location of the key icon on the screen.
Next step: put together a training set. They rigged up a simple automatic button-masher using a servo and some 3D-printed parts, and captured signals from the SDR for 100 presses of each key. The raw data was massaged a bit to prepare it for TensorFlow, and the trained network proved accurate enough to give any hardware wallet user pause – especially since they captured the data from two meters away with relatively simple and concealable gear.
Every lock contains the information needed to defeat it, requiring only a motivated attacker with the right tools and knowledge. We’ve covered other side-channel attacks before; sadly, they’ll probably only get easier as technologies like SDR and machine learning rapidly advance.
Data exfiltration via side channel attacks can be a fascinating topic. It is easy to forget that there are so many different ways that electronic devices affect the physical world other than their intended purpose. And creative security researchers like to play around with these side-effects for ‘fun and profit’.
Engineers at the University of California have devised a way to analyse exactly what a DNA synthesizer is doing by recording the sound that the machine makes with a relatively low-budget microphone, such as the one on a smart phone. The recorded sound is then processed using algorithms trained to discern the different noises that a particular machine makes and translates the audio into the combination of DNA building blocks the synthesizer is generating.
Although they focused on a particular brand of DNA Synthesizers, in which the acoustics allowed them to spy on the building process, others might be vulnerable also.
In the case of the DNA synthesizer, acoustics revealed everything. Noises made by the machine differed depending on which DNA building block—the nucleotides Adenine (A), Guanine (G), Cytosine (C), or Thymine (T)—it was synthesizing. That made it easy for algorithms trained on that machine’s sound signatures to identify which nucleotides were being printed and in what order.
Acoustic snooping is not something new, several interesting techniques have been shown in the past that raise, arguably, more serious security concerns. Back in 2004, a neural network was used to analyse the sound produced by computer keyboards and keypads used on telephones and automated teller machines (ATMs) to recognize the keys being pressed.
You don’t have to rush and sound proof your DIY DNA Synthesizer room just yet as there are probably more practical ways to steal the genome of your alien-cat hybrid, but for multi-million dollar biotech companies with a equally well funded adversaries and a healthy paranoia about industrial espionage, this is an ear-opener.
We written about other data exfiltration methods and side channels and this one, realistic scenario or not, it’s another cool audio snooping proof of concept.
Hardware wallets are devices used exclusively to store the highly sensitive cryptographic information that authenticates cryptocurrency transactions. They are useful if one is worried about the compromise of a general purpose computer leading to the loss of such secrets (and thus loss of the funds the secrets identify). The idea is to move the critical data away from a more vulnerable network-connected machine and onto a device without a network connection that is unable to run other software. When designing a security focused hardware devices like hardware wallets it’s important to consider what threats need to be protected against. More sophisticated threats warrant more sophisticated defenses and at the extreme end these precautions can become highly involved. In 2015 when [Jochen] took a look around his TREZOR hardware wallet he discovered that maybe all the precautions hadn’t been considered.
Continue reading “A Close Eye On Power Exposes Private Keys”
Small aircraft with streaming video cameras are now widely available, for better or worse. Making eyes in the sky so accessible has resulted in interesting footage that would have been prohibitively expensive to capture a few years ago, but this new creative frontier also has a dark side when used to violate privacy. Those who are covering their tracks by encrypting their video transmission should know researchers at Ben-Gurion University of the Negev demonstrated such protection can be breached.
The BGU team proved that a side-channel analysis can be done against behavior common to video compression algorithms, as certain changes in video input would result in detectable bitrate changes to the output stream. By controlling a target’s visual appearance to trigger these changes, a correlating change in bandwidth consumption would reveal the target’s presence in an encrypted video stream.
Continue reading “Watching The Watchers: Are You The Star Of An Encrypted Drone Video Stream?”
We’ve seen [Colin]’s entry to The Hackaday Prize before. After seeing his lightning talk at Defcon, we had to get an interview with him going over the intricacies of this very impressive piece of hardware.
The ChipWhisperer is a security and research platform for embedded devices that exploits the fact that all security measures must run on real hardware. If you glitch a clock when a microcontroller is processing an instruction, there’s a good probability something will go wrong. If you’re very good at what you do, you can simply route around the code that makes up the important bits of a security system. Power analysis is another trick up the ChipWhisperer’s sleeve, analyzing the power consumption of a microcontroller when it’s running a bit of code to glean a little information on the keys required to access the system. It’s black magic and dark arts, but it does work, and it’s a real threat to embedded security that hasn’t had an open source toolset before now.
Before our interview, [Colin] did a few short and sweet demos of the ChipWhisperer. They were extraordinarily simple demos; glitching the clock when a microcontroller was iterating through nested loops resulted in what can only be described as ‘counter weirdness’. More advanced applications of the ChipWhisperer can supposedly break perfectly implemented security, something we’re sure [Colin] is saving for a followup video.
You can check out [Colin]’s 2-minute video for his Hackaday Prize entry below.
Continue reading “The ChipWhisperer At Defcon”
There are thousands upon thousands of papers discussing various aspects of embedded hardware security, and dozens of books covering the same subject. The attacks discussed in the literature are very cool – things like side-channel power analysis and clock glitching used to extract keys from a system. The experimental setups in these papers are extraordinarily expensive – you can buy a new car for less. [coflynn] was disheartened with the price of these tools, and thought building his own would make for a great entry to The Hackaday Prize.
The hardware part of the ChipWhisperer includes a breakout board with an FPGA, ADC, and connectors for a lot of different probes, adapters, breakout boards, and a target board, With all these tools, it’s not unreasonable to say that [coflynn] could carry out a power analysis attack on a lot of embedded hardware.
Open source hardware is just one part of this entry. The biggest focus of this project is the open source software for analyzing whatever the probes and target boards record. With this software, anyone can monitor the power used when a chip runs a cryptographic function, or glitch a clock for some unintended functionality in a device. In keeping with the academic pedigree of all the literature on these attacks, there are a ton of tutorials for the ChipWhisperer for all those budding security researchers out there. Very cool stuff, and arguably one of the most technical entries to The Hackaday Prize.
The project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.
Continue reading “THP Entry: Embedded Hardware Security With The ChipWhisperer”