Timing Attack Vulnerability in SCRAM Authentication

Vulnerability Description

SCRAM (Salted Challenge Response Authentication Mechanism) is part of the family of Simple Authentication and Security Layer (SASL, RFC 4422) authentication mechanisms. Prior to version 3.2, a timing attack vulnerability exists in the SCRAM Java implementation. The issue arises because Arrays.equals was used to compare secret values such as client proofs and server signatures. Since Arrays.equals performs a short-circuit comparison, the execution time varies depending on how many leading bytes match. This behavior could allow an attacker to perform a timing side-channel attack and potentially infer sensitive authentication material. All users relying on SCRAM authentication are impacted. This vulnerability has been patched in version 3.1 by replacing Arrays.equals with MessageDigest.isEqual, which ensures constant-time comparison.

References

• https://github.com/ongres/scram/security/advisories/GHSA-3wfh-36rx-9537
• https://github.com/ongres/scram/commit/e0b0cf99f05406a0d26682c72fcb5728e95124b3
• https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/security/MessageDigest.html#isEqual(byte%5B%5D,byte%5B%5D)