Coldcard Firmware Vulnerability Drains Nearly $90M from Bitcoin Wallets

A security vulnerability in Coldcard firmware from March 2021 allowed attackers to drain nearly $89 million from 4,585 Bitcoin wallets. The attackers exploited weak key generation and targeted smaller balances with more complex transaction methods.

The attack occurred in three waves, with the most valuable keys mostly depleted. Galaxy Research suspects a single operator behind each wave but cannot confirm if all waves are linked.

This highlights risks in hardware wallet security and the importance of firmware updates to prevent similar attacks in the future.