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CIS Ubuntu 14.04 LTS - 1.6.2.1 Ensure AppArmor is not disabled in bootloader configuration

DevOps & Security
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Verify that AppArmor is not disabled via GRUB bootloader parameters

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_14.04_LTS_Benchmark_v2.1.0/cis-ubuntu1404-v210-1-6-2-1/SKILL.md

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1.6.2.1 Ensure AppArmor is not disabled in bootloader configuration (Scored)

Profile Applicability

  • Level 2 - Server
  • Level 2 - Workstation

Description

Configure AppArmor to be enabled at boot time and verify that it has not been overwritten by the bootloader boot parameters.

Rationale

AppArmor must be enabled at boot time in your bootloader configuration to ensure that the controls it provides are not overridden.

Audit Procedure

Run the following command and verify that no linux line the apparmor=0 parameter set:

grep "^\s*linux" /boot/grub/grub.cfg

Expected Result

No linux lines should contain apparmor=0.

Remediation

Edit /etc/default/grub and remove all instances of apparmor=0 from all CMDLINE_LINUX parameters:

GRUB_CMDLINE_LINUX_DEFAULT="quiet"
GRUB_CMDLINE_LINUX=""

Run the following command to update the grub2 configuration:

update-grub

Default Value

AppArmor is enabled by default on Ubuntu systems.

Notes

This recommendation is designed around the grub bootloader, if LILO or another bootloader is in use in your environment enact equivalent settings.

References

  1. AppArmor Documentation: http://wiki.apparmor.net/index.php/Documentation
  2. Ubuntu AppArmor Documentation: https://help.ubuntu.com/community/AppArmor
  3. SUSE AppArmor Documentation: https://www.suse.com/documentation/apparmor/

Profile

  • Level 2 - Server
  • Level 2 - Workstation