V-253903

Discussion

A replay attack may enable an unauthorized user to gain access to the application. Authentication sessions between the authenticator and the application 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. 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 Content

Determine if the network device implements replay-resistant authentication mechanisms for network access to privileged accounts. This requirement may be verified by demonstration, configuration review, or validated test results. This requirement may be met through use of a properly configured authentication server if the device is configured to use the authentication server. 

Verify SSH version 2 is configured for network (remote) access to privileged accounts.
[edit system services ssh]
protocol-version v2;

If the network device does not implement replay-resistant authentication mechanisms for network access to privileged accounts, this is a finding.