GHSA-g9mp-8g3h-3c5c flynn/noise has improper nonce handling yielding potential state DoS

• Go github.com/flynn/noise: < 1.0.0 → fixed in 1.0.0

The Go package `github.com/flynn/noise`, a Noise Protocol implementation, has two bugs in nonce handling in versions prior to v1.0.0. Issue 1: Potential nonce overflow If 264 (~18.4 quintillion) or more messages are encrypted with `Encrypt` after handshaking, the nonce counter will wrap around, causing multiple messages to be encrypted with the same key and nonce, resulting in a potentially catastrophic weakening of the security properties of the symmetric cipher. This has been resolved in the patched version by returning `ErrMaxNonce` from the `CipherState` `Encrypt` and `Decrypt` methods before the reserved maximum nonce is reached. If this error is encountered, the program should handshake again to start with a fresh `CipherState`. Issue 2: Potential denial of service via invalid ciphertext If an attacker sends an invalid ciphertext into one peer's `Decrypt`, the nonce is incremented unconditionally. This causes a desync of the `CipherState` due to a nonce mismatch between the peers, resulting in a failure to decrypt all subsequent messages. A new handshake will be required to establish a new `CipherState`. This has been resolved in the patched version by returning authentication errors from `Decrypt` before incrementing the nonce. Patches Fixed in https://github.com/flynn/noise/pull/44, tagged as v1.0.0. Acknowledgements These issues were discovered during an audit of a user of this package (dnstt). Thanks to UC Berkley for commissioning the audit, and to David Fifield and Nathan Brown for their collaboration on the fixes. The fixed issues are noted in the audit as: • UCB-02-003 Potential nonce overflow in Noise protocol • UCB-02-006 DoS due to unconditional nonce increment