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The Ubuntu operating system must enable and run the uncomplicated firewall(ufw).


Finding ID Version Rule ID IA Controls Severity
V-238355 UBTU-20-010434 SV-238355r654240_rule Medium
Remote access services, such as those providing remote access to network devices and information systems, which lack automated control capabilities, increase risk and make remote user access management difficult at best. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Ubuntu operating system functionality (e.g., RDP) must be capable of taking enforcement action if the audit reveals unauthorized activity. Automated control of remote access sessions allows organizations to ensure ongoing compliance with remote access policies by enforcing connection rules of remote access applications on a variety of information system components (e.g., servers, workstations, notebook computers, smartphones, and tablets).
Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide 2021-11-19


Check Text ( C-41565r654238_chk )
Verify the Uncomplicated Firewall is enabled on the system by running the following command:

$ systemctl is-enabled ufw

If the above command returns the status as "disabled", this is a finding.

Verify the Uncomplicated Firewall is active on the system by running the following command:

$ systemctl is-active ufw

If the above command returns "inactive" or any kind of error, 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-41524r654239_fix)
Enable the Uncomplicated Firewall by using the following command:

$ sudo systemctl enable --now ufw.service