Suspected Coldcard Exploit Attack Resurfaces, Approximately 388.93 Bitcoins Affected in New Round of Abnormal Transfers

TechFlow news, August 3, on-chain analyst Alex Thorn stated that a fourth round of organized attacks suspected to target Coldcard hardware wallets is underway. According to his observations, between blocks 960,778 and 960,792, within approximately the last 2.5 hours, a total of 218 transactions appeared, involving 462 victim addresses and 216 new target addresses, transferring a total of 388.92748828 BTC.

He pointed out that these transactions exhibit characteristics similar to UTXOs previously associated with suspected Coldcard vulnerabilities, and the abnormal transfer rate has significantly increased, approximately 45 times the baseline level before the incident. Some funds are currently still waiting for confirmation in the mempool, and confirmed transactions show support for Replace-By-Fee (RBF); affected users may still have the opportunity to replace them by increasing transaction fees. Additionally, some funds have been transferred to second-hop addresses.

Alex Thorn believes that these fund flow patterns highly match the characteristics of Coldcard-related vulnerable UTXOs, thus expressing high confidence that it is a new round of attack events, and reminds users to transfer funds from relevant devices as soon as possible, while setting higher transaction fees.