The Photon operating system must configure sshd to disallow Kerberos authentication.

If Kerberos is enabled through Secure Shell (SSH), sshd provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementation may then be subject to exploitation. To reduce the attack surface of the system, the Kerberos authentication mechanism within SSH must be disabled.

At the command line, run the following command:

# sshd -T|&grep -i KerberosAuthentication

Expected result:

KerberosAuthentication no

If the output does not match the expected result, this is a finding.

Navigate to and open:

/etc/ssh/sshd_config

Ensure the "KerberosAuthentication" line is uncommented and set to the following:

KerberosAuthentication no

At the command line, run the following command:

# systemctl restart sshd.service