Fourth Wave Sweeps 449 Bitcoin from Coldcard Wallets

A suspected fourth wave of coordinated attacks targeting Bitcoin wallets generated by vulnerable Coldcard hardware devices is underway, with blockchain researchers estimating nearly 449 Bitcoin, valued at approximately $28 million, has been swept from over 700 addresses on August 3. This latest activity brings the total estimated losses from four waves of attacks to roughly 1,816 Bitcoin, worth about $114 million, stolen from more than 5,200 addresses since the attacks began on July 30.

The research head at Galaxy Research, Alex Thorn, identified the latest wave through blockchain pattern analysis, noting the transactions matched the characteristics of wallets affected by a known firmware vulnerability. Thorn stated the addresses were "likely Coldcard victims" based on their transaction behavior, though he emphasized the findings were from blockchain data and not yet confirmed by law enforcement or the device manufacturer. The attack rate during this wave was measured at 13.8 wallet sweeps per Bitcoin block, a rate approximately 45 times higher than normal background activity.

Unlike earlier attacks, some of the unconfirmed transactions in this wave have signaled the...