V-240460

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 non-privileged account is any operating system account with authorizations of a non-privileged 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 Content

Verify that the SLES for vRealize enforces SSHv2 for network access to privileged accounts by running the following command:

Replace [ADDRESS] in the following command with the correct IP address based on the current system configuration.

# ssh -1 [ADDRESS]

An example of the command usage is as follows:
# ssh -1 localhost

The output must be one of the following items:

Protocol major versions differ: 1 vs. 2

OR:

Protocol 1 not allowed in the FIPS mode.

If the output is not one of the above, this is a finding.

OR 

Verify that the ssh is configured to enforce SSHv2 for network access to privileged accounts by running the following command:

# grep Protocol /etc/ssh/sshd_config

If the result is not "Protocol 2", this is a finding.