The Ubuntu operating system must have an application firewall enabled.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-238374 | UBTU-20-010454 | SV-238374r991593_rule | CCI-000366 | medium |
| Description | ||||
| Firewalls protect computers from network attacks by blocking or limiting access to open network ports. Application firewalls limit which applications are allowed to communicate over the network. | ||||
| STIG | Date | |||
| Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide | 2025-05-16 | |||
Details
Check Text (C-238374r991593_chk)
Verify the Uncomplicated Firewall is enabled on the system by running the following command:
$ systemctl status ufw.service | grep -i "active:"
Active: active (exited) since Mon 2016-10-17 12:30:29 CDT; 1s ago
If the above command returns the status as "inactive", this is a finding.
If the Uncomplicated Firewall is not installed, ask the System Administrator if another application firewall is installed. If no application firewall is installed, this is a finding.
Fix Text (F-41543r654296_fix)
Enable the Uncomplicated Firewall by using the following command:
$ sudo systemctl enable ufw.service
If the Uncomplicated Firewall is not currently running on the system, start it with the following command:
$ sudo systemctl start ufw.service