The Binance Trust Wallet app for iOS in commit 3cd6e8f647fbba8b5d8844fcd144365a086b629f, git tag 0.0.4 misuses the trezor-crypto library and consequently generates mnemonic words for which the device time is the only entropy source, leading to economic losses, as exploited in the wild in July 2023. An attacker can systematically generate mnemonics for each timestamp within an applicable timeframe, and link them to specific wallet addresses in order to steal funds from those wallets.
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG’s algorithm is not cryptographically strong.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Trust_wallet | Binance | 0.0.4 (including) | 0.0.4 (including) |
When a non-cryptographic PRNG is used in a cryptographic context, it can expose the cryptography to certain types of attacks. Often a pseudo-random number generator (PRNG) is not designed for cryptography. Sometimes a mediocre source of randomness is sufficient or preferable for algorithms that use random numbers. Weak generators generally take less processing power and/or do not use the precious, finite, entropy sources on a system. While such PRNGs might have very useful features, these same features could be used to break the cryptography.