Vulnerability Discussion

Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level.

Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline.

Methods for complying with this requirement include restricting execution of programs in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).

Check

Verify the operating system prevents program execution in accordance with local policies.

Check that apparmor is installed and active by running the following command:

# dpkg -l | grep apparmor

If the "apparmor" package is not installed, this is a finding.

#systemctl is-active apparmor.service

active

If "active" is not returned, this is a finding.

#systemctl is-enabled apparmor.service

enabled

If "enabled" is not returned, then this is a finding.

Fix

Install "Apparmor" (if it is not installed) with the following command:

# sudo apt-get install apparmor

# sudo systemctl enable apparmor.service

Start "Apparmor" with the following command:

# sudo systemctl start apparmor.service

Note: Apparmor must have properly configured profiles for applications and home directories. All configurations will be based on the actual system setup and organization and normally are on a per role basis. See the "Apparmor" documentation for more information on configuring profiles.