Vulnerability Discussion

A replay attack may enable an unauthorized user to gain access to the operating system. Authentication sessions between the authenticator and the operating system validating the user credentials must not be vulnerable to a replay attack.

An authentication process resists replay attacks if it is impractical to achieve a successful authentication by recording and replaying a previous authentication message.

A nonprivileged account is any operating system account with authorizations of a nonprivileged user.

Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one-time use) or challenges (e.g., TLS, WS_Security). Additional techniques include time-synchronous or challenge-response one-time authenticators.

Check

Verify the operating system implements replay-resistant authentication mechanisms for network access to nonprivileged accounts. If it does not, this is a finding.

Fix

Configure the operating system to implement replay-resistant authentication mechanisms for network access to nonprivileged accounts.