Trezor Wallets Also Compromised with Implants

Hardware hacker Joe Grand discovered malicious implants in two discontinued Trezor models - a Model T bought on Facebook Marketplace in Canada and a Trezor One acquired via a TikTok shop - and reported the findings to Trezor in August. Both devices came from unauthorized third‑party sellers, echoing earlier Kaspersky findings of a compromised Trezor sold on a Russian marketplace. Trezor privately engaged with Grand, requesting the extracted binary and noting similarities to previously observed counterfeit or modified units, but publicly stated it had no evidence of compromised devices while moving to de‑authorize a number of resellers as a precaution.

The implants worked by replacing the device microcontroller and loading malicious firmware that displays one of a small set of attacker‑known recovery seed phrases, allowing the attackers to reconstruct wallets. Because Trezor’s code is open source, attackers could adapt and reflash a replacement MCU; the modified devices also bypassed integrity checks by performing verification against a copy of legitimate firmware before switching to the compromised code. This method differs from the Ledger implants that quietly recorded true seeds at initialization and later transmitted them, a campaign that escalated to about $100 million stolen after implants appeared in devices from authorized sellers. The pattern of initial compromises via unauthorized sellers raises concern that similar implants could later appear in legitimately distributed stock.