Vulnerability Discussion
Failure to restrict system access to authenticated users negatively impacts operating system security.
Check
Verify the operating system does not allow users to override environment variables to the SSH daemon.
Check for the value of the "PermitUserEnvironment" keyword with the following command:
# grep -i permituserenvironment /etc/ssh/sshd_config
PermitUserEnvironment no
If the "PermitUserEnvironment" keyword is not set to "no", is missing, or is commented out, this is a finding.
Fix
Configure the operating system to not allow users to override environment variables to the SSH daemon.
Edit the "/etc/ssh/sshd_config" file to uncomment or add the line for "PermitUserEnvironment" keyword and set the value to "no":
PermitUserEnvironment no
The SSH service must be restarted for changes to take effect.