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Case study: fake hardware cryptowallet

kaspersky.com

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Re: Case study: fake hardware cryptowallet

#131

Post by londons_explore »

StingyJelly wrote: post #40
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.

More sophisticated version of the malicious firmware could try to patch the new ota firmware image on the fly. Once compromised - always compromised.

It's hard to reliably binary patch something unknown ahead of time.

All Trezor would need to do is change the compilation options on a fairly regular basis, and any patching will fail.

Combine with the fact there is a reward to send in devices means they can analyze any evil devices and make sure their instructions to users will reliably detect all evil devices they're aware of.

Still doesn't stop supply chain attacks, but makes them far harder.

Re: Case study: fake hardware cryptowallet

#132

Post by mattdesl »

dools wrote: post #100
lxgr wrote: post #49

Earlier quoted context omitted.

You have to trust somebody when it comes to hardware devices. If you don't do anything, that includes the OEM, their supply chain, your delivery courier, an evil maid etc. If you have the choice of reducing that list to only the OEM, isn't that a win? That's what attestation does.

> You have to trust somebody I know, all the time, and thus the entire premise of crypto is flawed, as are the libertarian ideals that birthed it.

“Trustless” is one of those crappy words that implies there is zero trust in the system. Obviously this is not true - you trust the protocol, the contracts, the hardware wallet supply chain. Hell, you have to trust that ECDSA is not broken.

Still, when we talk about ECDSA and other cryptographic protocols, you can use them without being forced to place your trust in the hands of a single person or private company. There isn’t really a great term to describe that ethos, so “trustless” is often used in place.

Re: Case study: fake hardware cryptowallet

#133

Post by mattdesl »

lottin wrote: post #123
PretzelPirate wrote: post #104

Earlier quoted context omitted.

> trustless system Crypto let's you choose who to trust. You can build your own wallet, you can buy one, or you can choose to let someone hold your assets for you. Many people will choose to trust large centralized parties, and some will choose to generate their own keys offline with code they've verified. Do they have to trust that any cryptographic libraries they use generate seeds properly? Yes, but there are plen…

Nobody can build their own wallet directly from raw materials. Even in the very unlikely event that they had the know-how, they would still require highly specialised equipment manufactured by third parties. Therefore users of "crypto" have no option but to rely on goods and services provided by third parties just like everybody else. And the extent to which consumers can choose which parties to rely on (or "trust")…

It’s not that hard to build your own wallet software, or if you really want, a paper wallet using dice and a pen.

But frankly it’s not that different than cryptography as a whole: nobody implements ECDSA themselves, or builds the computer that runs it, or smelt the metal and assemble transistors that runs the computer, or whatever. There is no such thing as “absolute lack of trust” but some protocols can be “less trust requiring” than others—e.g. more “trustless.”

Re: Case study: fake hardware cryptowallet

#135

Post by mattdesl »

mrb wrote: post #62

I would be immune to this attack because I always generate my own seeds, on a trusted computer. So I set up hardware wallets to import my seed, instead of trusting their seed generation algo. Of course this procedure doesn't protect against other hardware attacks, for example the wallet exfiltrating the private key somehow (R/F signal), but it certainly raises the bar for hackers.

Although you do open yourself to vulnerabilities in how you generate your random entropy—for average user, it might be worse than relying on a hardware wallet.

The safest play here for an average user is to just not buy your hardware wallets off eBay, as it seemed to be the case in the OP!

Re: Case study: fake hardware cryptowallet

#136

Post by quickthrower2 »

CTDOCodebases wrote: post #125
rippercushions wrote: post #83

Earlier quoted context omitted.

Obligatory $5 wrench xkcd: https://xkcd.com/538/ Still, physically threatening/kidnapping somebody is an entirely different threat model, although it's very common in the Bitcoin world: https://github.com/jlopp/physical-bitcoin-attacks

This is not specific to Bitcoin though. In Latin America there are “Flash/lightening kidnappings” where they take a person hostage and drain their bank account over a period of time.

They can’t take a bank hostage and drain all of it’s customers funds though.

Re: Case study: fake hardware cryptowallet

#137

Post by lottin »

mattdesl wrote: post #133
lottin wrote: post #123

Earlier quoted context omitted.

Nobody can build their own wallet directly from raw materials. Even in the very unlikely event that they had the know-how, they would still require highly specialised equipment manufactured by third parties. Therefore users of "crypto" have no option but to rely on goods and services provided by third parties just like everybody else. And the extent to which consumers can choose which parties to rely on (or "trust")…

It’s not that hard to build your own wallet software, or if you really want, a paper wallet using dice and a pen. But frankly it’s not that different than cryptography as a whole: nobody implements ECDSA themselves, or builds the computer that runs it, or smelt the metal and assemble transistors that runs the computer, or whatever. There is no such thing as “absolute lack of trust” but some protocols can be “less tru…

How does a "paper wallet" work? I thought a wallet in order to work had to interact with other wallets?

Re: Case study: fake hardware cryptowallet

#138

Post by amenghra »

amenghra wrote: post #120
lxgr wrote: post #93

Earlier quoted context omitted.

Even more concerning than predictable wallet seeds are covert channels in the form of nondeterministic signature outputs. Most wallets let you provide your own seed words, which users can derive using diceware themselves, but DSA (and its elliptic-curve variants) need a secure random input, and I'm not sure if all wallets commonly use a deterministic (i.e. provably free of covert channels) construction (like in RFC 6…

From the outset, you can't prove that RFC 6979 was used. I.e. RFC 6979 doesn't provide provable security. If you want a proof that there are no covert channels, you need to implement some kind of interactive protocol between the signer and the verifier -- I'm not aware of any standard/popular way of implementing that. What you can do is use a dice to generate a key and the sign a bunch of messages with your hardware…

The best defense against potentially malicious hardware wallets is to set up a multisig scheme. If designed properly (with careful planning related to backup/recovery), you end up with better security properties (i.e. defense in depth).

Re: Case study: fake hardware cryptowallet

#139

Post by Philadelphia »

RalfWausE wrote: post #134
kosherhurricane wrote: post #94

My #1 argument against the feasibility of cryptocurrency: Can my parents not their get money stolen?

This is an argument against any form of direct payment... i mean, you can get your cash stolen very easily...

Yes. And so cryptocurrency is a reversion to a model of payment that’s been rejected by most people for its poor security.

Re: Case study: fake hardware cryptowallet

#140

Post by pjc50 »

paulpauper wrote: post #114
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…

The surface of attack is so big, no one should use hardware wallets for anything more than beer money

And you shouldn't keep your keys on a regular computer, because that has an even bigger attack surface, nor should you use an exchange which may rugpull you.
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