$100M DRAINED From Crypto's Safest Wallet!

Between July 30-August 3, 2026, attackers drained approximately $100 million in Bitcoin from thousands of Cold Card hardware wallets through an automated attack that didn't require accessing the physical devices. The root cause was a firmware bug introduced on March 1, 2021, when Cold Card migrated to a new cryptography library called Libangu. A single line of code checked whether a hardware randomness setting existed rather than whether it was enabled, causing the firmware to skip the hardware random number generator and fall back to a weak software generator called Yasmarang that relied on the chip's serial number and startup timing—values an attacker could guess or enumerate. On Cold Card MK2 and MK3 devices, this reduced seed phrase security from 128 bits to approximately 40 bits (about one trillion possibilities), small enough for a laptop to crack offline in hours. Newer MK4, MK5, and Q models retained around 72 bits due to additional randomness from secure chips. The bug went undetected for five years because the hardware randomness generator was still present and functional elsewhere in the firmware, passing internal reviews, but the specific code path generating seed phrases bypassed it entirely. Victims included people who followed all recommended security practices, stored devices offline in safes and vaults, and never touched their wallets—some losing funds that had sat untouched for over three years. The attack affected not just seed phrases but also paper wallet keys, seed XR split masks, device cloning keys, USB encryption keys, and other sensitive cryptographic material. Three groups survived completely unaffected: users who rolled physical dice (at least 50 rolls) during setup to inject real randomness, users who added a strong BIP39 passphrase, and users in genuine multi-signature setups. No multi-sig wallets or Taproot addresses were hit, indicating the attacker's script was narrowly scoped. Cold Card CEO NVK responded quickly, taking full accountability and advising users to move funds immediately, but updating firmware only prevents new bad keys—it cannot fix already-generated compromised seeds. Cold Card's deliberate 120-day customer record purge for privacy prevented mass notification of affected users. The incident reflects a broader pattern in crypto: randomness bugs are recurring failure points across the industry that go undetected because weak randomness produces no visible symptoms. Similar bugs have caused major losses—the 2023 Milk Sad bug ($900K+), the 2022 Profanity vanity tool ($160 million), Trust Wallet's 2022-2023 browser extension flaw, and the July 2026 Ill Bloom bug ($5M+ across blockchains). The analysis concludes that survivors upgraded their security through additional safeguards they implemented themselves—not because they anticipated this specific bug, but from general paranoia about security. The incident demonstrates that verifiable self-custody (with dice rolls, passphrases, or multi-sig) now beats trusted self-custody, and that the open-source ecosystem's ability to find, patch, and transparently verify fixes within days exceeds traditional custodian transparency.