The FortiGate device must implement replay-resistant authentication mechanisms for network access to privileged accounts.

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.

Log in to the FortiGate GUI with Super-Admin privilege. 1. Open a CLI console, via SSH or available from the GUI. 2. Run the following command: # show full-configuration system global | grep -i 'tls\|ssh-v' The output should be: # set admin-https-ssl-versions tlsv1-2 tlsv1-3 # set admin-ssh-v1 disable # set ssl-min-proto-version TLSv1-2 #end If admin-https-ssl-versions is not set to tlsv1-2 tlsv1-3 or admin-ssh-v1 is enable, this is a finding.

Log in to the FortiGate GUI with Super-Admin privilege. 1. Open a CLI console, via SSH or available from the GUI. 2. Run the following command: # config system global # set admin-https-ssl-versions tlsv1-2 tlsv1-3 # set admin-ssh-v1 disable # end