Coldcard Security Breach: 1,359.882 BTC Stolen, Attacker’s Address Receives 10% Crypto Laundering Offer

In the security incident involving Coldcard, the hardware wallet brand under Coinkite, the number of stolen bitcoins has risen to approximately 1,359.882 BTC. According to statistics from the Coldcard Sweep Watch dashboard, most of the identified stolen bitcoins remain in a small number of addresses controlled by the attackers. On August 1, one of the attackers' holding addresses received a transaction containing OP_RETURN data. The data publicly offered bitcoin "cleaning" services, KYC assistance, and illicit fund withdrawal services for a 10% fee, along with a Telegram contact. Coinkite has released an emergency firmware update to resolve the weak random number generation issue that caused the original vulnerability. The company noted that the new firmware only protects wallets created in the future and cannot repair seeds generated in affected versions. Some users have reported that after installing the update, their devices get stuck on error screens, fail to boot, or are potentially bricked, with issues primarily affecting Mk4 and Q models, while Mk3 users have also reported similar problems. As of August 2, Coinkite has not publicly confirmed the existence of widespread firmware defects.