Fake Trezor Wallets Designed to Steal Bitcoin Spotted in the Wild
"It looks and feels like a Trezor wallet, but puts all your crypto-investments into the hands of criminals."
"It was a classic supply-chain attack in which an unsuspecting victim buys an already-hacked device."
A victim seemingly lost 1.334 BTC after depositing funds into an address displayed by the device.
"The fake cryptowallet would operate as normal, but the attackers had full control over it from the very beginning. According to the transaction history, they were in no hurry, waiting a whole month after the wallet was credited for the first time before they grabbed the money. The owner had no protection whatsoever: the game was lost from the very moment the money first arrived in the Trojan wallet."
"The unit was bought from a trusted seller through a popular classifieds website, and the holographic stickers on the box and the wallet itself were all present and undamaged."
"Instead of the original STM32F427, the unit had an STM32F429 with fully deactivated microcontroller flash-memory read-out protection mechanisms (RDP 0 instead of RDP 2 in genuine Trezors)."
"The bootloader-checks for protection mechanisms and digital signatures were removed, thus getting rid of the “red screen” problem during the firmware originality check at startup."
"At the initialization stage or when resetting the wallet, the randomly generated seed phrase was replaced with one of 20 pre-generated seed phrases saved in the hacked firmware. The owner would begin using it instead of a new and unique one."
"If the user chose to set an additional master-seed protection password, only its first symbol (a…z, A…Z, 0…9 or ! for any special character) was used, which, together with the no-password option, gave just 64 possible combinations. Thus, to crack a given fake wallet, only 64*20=1280 variants were to be considered."
"The main safeguard is to buy your wallet directly from the official vendor and choose models with special versions of protected microcontrollers (even original Trezors aren’t ideal in this sense: there are other brands’ wallets with better protected chips and extra protection mechanisms)."