Coldcard Users Warned of New Wave of Coordinated Thefts

A new wave of coordinated thefts is targeting Bitcoin hardware wallets from company Coldcard. This follows the disclosure of a previously undetected firmware flaw that has affected over 1,100 devices and led to an estimated $90 million in stolen Bitcoin. The latest attack has swept around 389 BTC, with researcher Alex Thorn flagging 218 transactions impacting 462 potential victim addresses.

Thorn stated that the activity 'likely' matches attacks on Coldcard users, given the elevated transaction pattern. He noted that most transfers have seen a fresh destination created for each victim rather than converging on a central collection wallet, and some funds have been swept into second hop addresses.

Affected users who control the relevant keys may be able to broadcast a conflicting transaction with a higher fee to move their funds to a secure wallet before the attacker's transaction is confirmed. Thorn warned of similar transactions in the mempool waiting to be confirmed.