RHEL 9 must disable the chrony daemon from acting as a server.

Minimizing the exposure of the server functionality of the chrony daemon diminishes the attack surface.

Satisfies: SRG-OS-000096-GPOS-00050, SRG-OS-000095-GPOS-00049

Note: If the server is serving as an NTP server, this is not applicable.

Verify RHEL 9 disables the chrony daemon from acting as a server with the following command:

$ grep -w port /etc/chrony.conf

port 0

If the "port" option is not set to "0", is commented out, or is missing, this is a finding.

Configure RHEL 9 to disable the chrony daemon from acting as a server by adding/modifying the following line in the /etc/chrony.conf file:

port 0