RUSTSEC-2022-0093

Dashboard / Vulnerabilities / RUSTSEC-2022-0093

RUSTSEC-2022-0093

Summary: Double Public Key Signing Function Oracle Attack on `ed25519-dalek`

Details: Versions of `ed25519-dalek` prior to v2.0 model private and public keys as separate types which can be assembled into a `Keypair`, and also provide APIs for serializing and deserializing 64-byte private/public keypairs. Such APIs and serializations are inherently unsafe as the public key is one of the inputs used in the deterministic computation of the `S` part of the signature, but not in the `R` value. An adversary could somehow use the signing function as an oracle that allows arbitrary public keys as input can obtain two signatures for the same message sharing the same `R` and only differ on the `S` part. Unfortunately, when this happens, one can easily extract the private key. Revised public APIs in v2.0 of `ed25519-dalek` do NOT allow a decoupled private/public keypair as signing input, except as part of specially labeled "hazmat" APIs which are clearly labeled as being dangerous if misused.

References: https://crates.io/crates/ed25519-dalek, https://rustsec.org/advisories/RUSTSEC-2022-0093.html, https://github.com/MystenLabs/ed25519-unsafe-libs