COLDCARD Hack Exposes Vulnerability in Offline Wallets, 2,000 BTC Stolen
A COLDCARD hardware wallet hack has resulted in the theft of over 2,000 BTC. The attack, which occurred on July 30, targeted more than 7,300 addresses and drained 1,082.65 BTC from 1,196 addresses within 41 minutes. Galaxy Research estimates that the total amount stolen is around 1,596 BTC, with a further 448.7 BTC potentially linked to the vulnerability.
The hackers exploited a firmware build error in COLDCARD's air-gapped wallets, which allowed them to guess vulnerable seeds and reconstruct private keys without physical access to the devices. The issue was caused by MicroPython's predictable Yasmarang pseudorandom number generator being used instead of the device's hardware random number generator.
CoinKite has released firmware upgrades to fix the issue, but these do not repair old seed phrases. Multiple users have moved their Bitcoin to new wallets or chosen multi-signature wallets to avoid similar vulnerabilities.
Experts believe that the stolen BTC will be difficult to liquidate due to exchanges and other centralized intermediaries flagging and monitoring addresses linked to the stolen funds. White-hat hackers are working to reclaim the stolen BTC, making it a time-bound challenge for them to monetize their loot.