Coldcard security incident resulted in the theft of 1359.882 BTC, with the attacker's address receiving a 10% laundering offer

In the security incident involving Coldcard, a hardware wallet company under Coinkite, the amount of stolen Bitcoin has risen to approximately 1359.882 coins. The Coldcard Sweep Watch dashboard statistics show that most of the identified Bitcoin still remains in a few addresses controlled by the attacker.

On August 1, a holding address of the attacker received a transaction containing OP_RETURN information. This information publicly offered "cleaning" Bitcoin, KYC assistance, and cash-out services for a 10% fee, along with a Telegram contact.

Coinkite has released an emergency firmware update to eliminate the weak random number generation issue that caused the original vulnerability. The company stated that the new firmware only protects wallets created in the future and cannot fix seeds generated in the affected versions.

Some users reported that after installing the update, their devices remained on an error page, failed to start, or appeared to be bricked, mainly involving Mk4 and Q devices, with some Mk3 users reporting similar issues. As of August 2, Coinkite has not publicly confirmed the existence of widespread firmware defects.