The Photon operating system must configure Secure Shell (SSH) to disallow Generic Security Service Application Program Interface (GSSAPI) authentication.

GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through Secure Shell (SSH) exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system.

At the command line, run the following command to verify the running configuration of sshd:

# sshd -T|&grep -i GSSAPIAuthentication

Example result:

gssapiauthentication no

If "GSSAPIAuthentication" is not set to "no", this is a finding.

Navigate to and open:

/etc/ssh/sshd_config

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

GSSAPIAuthentication no

At the command line, run the following command:

# systemctl restart sshd.service