Case study: fake hardware cryptowallet • Hacker News Board

Re: Case study: fake hardware cryptowallet

#21

Post by hn_throwaway_99 » Mon, May 15, 2023, 10:39 PM UTC

monero-xmr wrote: post #7

If you want a hardware wallet, I recommend software in an air-gapped machine. Unless you can buy the hardware directly from the manufacturer, and ideally you walked into the factory and bought it at the source, the risk of compromise is too great.

I don't understand this. If you ever want to do anything with the funds in that wallet (e.g. sign transactions using the private key), you're going to need to connect it to a machine that can connect to the Internet. Otherwise, how is this any better than a cold storage paper wallet?

Re: Case study: fake hardware cryptowallet

#22

Post by lisper » Mon, May 15, 2023, 10:41 PM UTC

I foresaw this years ago, which prompted me to build this:

https://sc4.us/hsm/

It's an HSM which you can flash yourself. Unfortunately, it never generated much interest and so I had to fold up the tent. But maybe it was just ahead of its time.

Re: Case study: fake hardware cryptowallet

#23

Post by TacticalCoder » Mon, May 15, 2023, 10:41 PM UTC

Another nasty supply chain attack exists, way simpler (unlikely to work on knowledgeable users though)... A legit hardware wallet is shipped, but with fake documentation accompanying it. Some evil people working for delivery companies would swap legit hardware wallet for the exact same model, but with documentation using the official company's logo and font and saying, basically:

"Here's your hardware wallet, initialize it with the seed written on this piece of paper, it's the only one that's going to work for this hardware wallet. Do not lose this seed or you'll lose access to your funds!".

Several unsuspecting users, not aware that a random seed is supposed to be generated by the hardware wallet (or by throwing dice, or whatever) have been pwned this way.

Re: Case study: fake hardware cryptowallet

#24

Post by munificent » Mon, May 15, 2023, 10:46 PM UTC

> The bootloader checks the digital signature of the firmware and, if an anomaly is detected, displays an unoriginal firmware message and deletes all the data in the wallet.

This seems like a horrendous design, like a safe that burns the money inside if you try to tamper with it. Sure, it might protect a malicious thief from absconding with the funds, but it is also an attack vector for any bad actor that simply wishes to cause you harm.

Re: Case study: fake hardware cryptowallet

#25

Post by bibaheu » Mon, May 15, 2023, 10:46 PM UTC

hn_throwaway_99 wrote: post #21

monero-xmr wrote: post #7

If you want a hardware wallet, I recommend software in an air-gapped machine. Unless you can buy the hardware directly from the manufacturer, and ideally you walked into the factory and bought it at the source, the risk of compromise is too great.

I don't understand this. If you ever want to do anything with the funds in that wallet (e.g. sign transactions using the private key), you're going to need to connect it to a machine that can connect to the Internet. Otherwise, how is this any better than a cold storage paper wallet?

You can generate the coin movement operation in the air gapped machine, write it down on paper, and then use a normal, connected computer to transmit it to the network. The private key never left the air gapped machine, with this method.

Re: Case study: fake hardware cryptowallet

#26

Post by Gigachad » Mon, May 15, 2023, 10:46 PM UTC

TacticalCoder wrote: post #23

Another nasty supply chain attack exists, way simpler (unlikely to work on knowledgeable users though)... A legit hardware wallet is shipped, but with fake documentation accompanying it. Some evil people working for delivery companies would swap legit hardware wallet for the exact same model, but with documentation using the official company's logo and font and saying, basically: "Here's your hardware wallet, initial…

There have also been cases of software using malicious seed generators which have semi predictable outputs. People assume it’s safe because they see what looks like random seeds, combined with no network activity. But the attacker can then just scan over the whole possible key space and check for funds.

Re: Case study: fake hardware cryptowallet

#27

Post by Scoundreller » Mon, May 15, 2023, 10:46 PM UTC

alden5 wrote: post #20

Scoundreller wrote: post #8

> The housing was difficult to open: its two halves were held together with liberal quantities of glue and double-sided adhesive tape instead of the ultrasonic bonding used on factory-made Trezors. Other than having x-ray vision, one easy (but by no means perfect) verification to thwart these types of attacks is to weigh your devices. Manufacturing should be consistent enough that resealing a device like this would b…

the problem is the sorta person to buy a wallet from a classifieds website isn't willing to spend $30 on a scale to weigh it, because if they had that money they'd just buy it from the official store instead

Lifehack: a post office will weigh whatever you want for free. Also many grocery stores have accessible scales.

Best part is they pay for the certifications!

Then there are friends that ahem buy/sell materials in gram quantities. A counted handful of newish coins are a reasonable way of verifying accuracy in those cases. Be sure to weigh different quantities lest the absolute and relative error cancel out.

Re: Case study: fake hardware cryptowallet

#28

Post by wmf » Mon, May 15, 2023, 10:46 PM UTC

radicaldreamer wrote: post #19

londons_explore wrote: post #17

Earlier quoted context omitted.

If I were Trezor and became aware of a fake firmware, I would: * Offer rewards to anyone able to send me the fake devices or clues who is making them. * Tell my clients to upgrade the firmware on devices before use. Make sure every new firmware is distinctive in some way - for example the boot screen, and tell the users to check for that to ensure they are actually running the firmware they thought they just flashed.

Seems like this could also be an insider threat where someone at Trezor knew all the BOM details and could pull this off

Trezor is mostly open hardware and open source firmware to begin with.

Re: Case study: fake hardware cryptowallet

#29

Post by drexlspivey » Mon, May 15, 2023, 10:46 PM UTC

hn_throwaway_99 wrote: post #21

monero-xmr wrote: post #7

If you want a hardware wallet, I recommend software in an air-gapped machine. Unless you can buy the hardware directly from the manufacturer, and ideally you walked into the factory and bought it at the source, the risk of compromise is too great.

I don't understand this. If you ever want to do anything with the funds in that wallet (e.g. sign transactions using the private key), you're going to need to connect it to a machine that can connect to the Internet. Otherwise, how is this any better than a cold storage paper wallet?

You don’t need to connect it to a networked machine to sign a transaction though? You sign the transaction in the airgapped machine, a signed transaction is just a hex string. Move it to the networked machine and broadcast it.

Re: Case study: fake hardware cryptowallet

#30

Post by themagician » Mon, May 15, 2023, 10:48 PM UTC

hn_throwaway_99 wrote: post #21

monero-xmr wrote: post #7

If you want a hardware wallet, I recommend software in an air-gapped machine. Unless you can buy the hardware directly from the manufacturer, and ideally you walked into the factory and bought it at the source, the risk of compromise is too great.

I don't understand this. If you ever want to do anything with the funds in that wallet (e.g. sign transactions using the private key), you're going to need to connect it to a machine that can connect to the Internet. Otherwise, how is this any better than a cold storage paper wallet?

You don't, actually. Coldcard works without ever having to be online. You sign transactions on an SD card and just swap it.