Everything You Didn’t Know You Need To Know About Glitching Attacks

If you’ve always been intrigued by the idea of performing hardware attacks but never knew where to start, then we’ve got the article for you: an in-depth look at the hows and whys of hardware glitching.

Attentive readers will recall that we’ve featured [Matthew Alt]’s reverse engineering exploits before, like the time he got root on a Linux-based arcade cabinet. For something a bit more challenging, he chose a Trezor One crypto wallet this time. We briefly covered a high-stakes hack (third item) on one of these wallets by [Joe Grand] a while back, but [Matthew] offers much, much more detail.

After introducing the theory of glitching attacks, which seek to force a processor into an undefined state using various methods, [Matthew] discusses the specifics of the Trezor wallet and how the attack was planned.

His target — the internal voltage regulator of the wallet’s STM32 microcontroller — required desoldering a few caps before the attack could begin, which was performed with a ChipWhisperer. After resolving a few initial timing issues, he was able to glitch the chip into dropping to the lowest level of readout protection, which gave access to the dongle’s SRAM through an ST-Link debugger.

While this summary may make the whole thing sound trivial, it’s obvious that the attack was anything but, nor was the effort that went into writing it all up. The whole thing reads a little like a techno-thriller, and there’s plenty of detail there if you’re looking for a tutorial on chip glitching. We’re looking forward to part 2, which will concentrate on electromagnetic fault-injection using a PicoEMP and what looks like a modified 3D printer.

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Hackaday Links: January 30, 2022

After all the fuss and bother along the way, it seems a bit anticlimactic now that the James Webb Space Telescope has arrived at its forever home orbiting around L2. The observatory finished its trip on schedule, arriving on January 24 in its fully deployed state, after a one-month journey and a couple of hundred single-point failure deployments. The next phase of the mission is commissioning, and is a somewhat more sedate and far less perilous process of tweaking and trimming the optical systems, and getting the telescope and its sensors down to operating temperature. The commissioning phase will take five or six months, so don’t count on any new desktop photos until summer at the earliest. Until then, enjoy the video below which answers some of the questions we had about what Webb can actually see — here’s hoping there’s not much interesting to see approximately in the plane of the ecliptic.

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Hacking Hardware Bitcoin Wallets: Extracting The Cryptographic Seed From A Trezor

It’s long been common wisdom that one of the safest places to keep your cryptocurrency holdings is in a hardware wallet. These are small, portable devices that encrypt your keys and offer a bit more peace of mind than holding your coins in a soft or web wallet.

But of course, as we know, nothing is totally secure.

And we were reminded of this fact by Kraken Security Labs, when they showed us how they bypassed all of the safeguards in a popular wallet, the Trezor, to dump and decrypt it’s seed.

It’s worth noting that the hack does require physical access to the wallet — albeit only about fifteen minutes worth. And by “physical access” we mean that the hack leaves the device thoroughly mutilated. The Kraken team started by desoldering the heart of the wallet, a STM32 processor. They then dropped it into a socket on an interface board, and got to glitching.

The hack relies on an attack known as voltage glitching. Essentially, at a precisely-timed moment during the device’s boot sequence, the supply voltage is fluctuated. This enables the chip’s factory bootloader, which can read out the contents of it’s onboard flash memory. The memory is read-protected, but can be accessed 256 bytes at a time through a second voltage glitch. Neither of these attacks work 100% of the time, so if the device fails to boot or the memory remains locked, the FPGA performing the attacks simply tries again. After enough iterations, the Kraken team was able to fully dump the chip’s flash memory.

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A Close Eye On Power Exposes Private Keys

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.

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