Large-scale Coldcard compromise (1485.77 BTC stolen so far)

[kTimesG]

So here's the real deal, not theoretical blah-blah (which got it wrong):

1. The entire attack was already over by Aug 2nd.
2. Most likely each wave belonged to a different entity.
3. There's most likely a lot of missed mini-waves or whatever (each block that mined TXs of more than 1 separate compromised account are unlikely to belong to same owner).

Why I am all but sure about this? I reversed engineer the actual process. The first compromised seed had its initial income address funded on March 18 2021, 19:11:04 GMT. That is exactly one day after v4.0.0 of the firmware was released. All of the accounts that I was able to detect (~ 2050) that still had a balance on Jul. 30 were already sweeped in the last week. That is more than 1200 accounts (more than half of all the compromised seeds) being moved in just the first 48 hours after first wave.

Or more practical: 10654 different addresses moved out funds in the last week. Which is a third of all addresses of all accounts.

The only thing left are three dust addresses totalling less than 1000 satoshis. Everything else is gone, so that explains why the attackers moved to weak passphrases; there was nothing else left to do. Do not think dice rolls helped, those wallets do exist, and are also gone.

I don't think it will be a long time before the security researchers will revise their numbers for the CC actual security bits (it is not even close to 40).

Note: this didn't take months of preparation or trillions of scans. It's simply just a catastrophic system failure on the firmware coder's part. The first attacker simply probably didn't bother to dig deeper, while the subsequent ones did.

[vapourminer]

The Coldcard case made it clear, at the very least, that creating a wallet, writing down the seed phrase, depositing some funds, and only opening the wallet 10 years later IS NOT ENOUGH. A strategy for acting during trips is more than necessary.

many many decades ago i used to hide things like a PINs and other codes as phone numbers on a piece of paper. like Vivian xxx-xxx-xxxx would have the PIN for my Visa debit card or things along those lines.. door codes etc.

back then before smartphones no one looked twice at a phone list. now a printed phone list would probably be sus in itself.

now? need to hide 128 bits worth somewhere.

[bitmover]

I would rather just buy a hardware wallet and add a passphrase.

Or you can just flip a coin 256 times and add results to iancoleman.io

Dont need to buy anything too fancy

[sergiorus]

Coldcard Maker Coinkite Says It Will Publish Post-Mortem, Declines to Estimate Customer Losses

Bloomberg reported that Coinkite, the maker of the Coldcard Bitcoin hardware wallet, said it is focused on assisting customers affected by the security incident and will publish a post-mortem once its full investigation is complete, rather than speculate on the scale of customer losses. Coinkite said the privacy-focused design of its products prevents it from independently verifying external estimates of the amount stolen. Recent outside research has raised estimated losses from the attack to roughly $130 million.




Source: https://www.bloomberg.com/news/articles/2026-08-06/hacked-bitcoin-wallet-maker-declines-to-estimate-amount-lost

[Pmalek]

I have mixed thought about it. I can see OpenSats actually fund this person[1] and AFAIK OpenSats generally fund promising person and project. But i also worry about quality/accuracy of their finding. "27.5 hours in, we've filed 4,962 findings across 390 projects" from 16 people and some AI sounds too high/fast. Either way, we'll know how accurate are their findings, by looking at release note of wallet and other cryptocurrency software/library in next few months.

A few posts down in the thread whose link I posted in my previous post, calle says that the severity of the findings has already been confirmed by (some) projects. They say that certain teams have upgraded while others have downgraded their software releases. I think it's going to be difficult to find out how much of an impact those findings had. Software is regularly updated and unless the developers publicly acknowledge calle's help, we won't know if it's a regular update, an update based on findings from their own team, or an update performed because of vulnerabilities and issues found by the Bitcoin Red Team.