X11 forwarding for SSH must be disabled.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-216114SRG-OS-000480SOL-11.1-040330SV-216114r959010_rule2024-11-253
Description
As enabling X11 Forwarding on the host can permit a malicious user to secretly open another X11 connection to another remote client during the session and perform unobtrusive activities such as keystroke monitoring, if the X11 services are not required for the system's intended function, they should be disabled or restricted as appropriate to the user's needs.
ℹ️ Check
Determine if X11 Forwarding is enabled. # grep "^X11Forwarding" /etc/ssh/sshd_config If the output of this command is not: X11Forwarding no this is a finding.
✔️ Fix
The root role is required. Modify the sshd_config file. # pfedit /etc/ssh/sshd_config Locate the line containing: X11Forwarding Change it to: X11Forwarding no Restart the SSH service. # svcadm restart svc:/network/ssh