Title

The Ubuntu operating system must not allow users to override SSH environment variables. (Cat II impact)

Discussion

Failure to restrict system access to authenticated users negatively impacts Ubuntu operating system security.

Check Content

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 Text

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: # sudo systemctl restart sshd.service

Additional Identifiers

Rule ID: SV-215127r610931_rule

Vulnerability ID: V-215127

Group Title: SRG-OS-000480-GPOS-00229

Expert Comments

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