Side-Channel Vulnerability in BIP-39 Mnemonic Processing on Trezor Wallets Enables Mnemonic Exposure

A side-channel vulnerability exists in the implementation of BIP-39 mnemonic processing, as observed in Trezor One v1.13.0 to v1.14.0, Trezor T v1.13.0 to v1.14.0, and Trezor Safe v1.13.0 to v1.14.0 hardware wallets. This originates from the BIP-39 standard guidelines, which induce non-constant time execution and specific branch patterns for word searching. An attacker with physical access during the initial setup phase can collect a single side-channel trace. By utilizing profiling-based Deep Learning Side-Channel Analysis (DL-SCA), the attacker can recover the mnemonic code and subsequently steal the assets. The issue was patched.

BIP-143 in the Bitcoin protocol specification mishandles the signing of a Segwit transaction, which allows attackers to trick a user into making two signatures in certain cases, potentially leading to a huge transaction fee. NOTE: this affects all hardware wallets. It was fixed in 1.9.1 for the Trezor One and 2.3.1 for the Trezor Model T.