Disable Mounting of hfsplus

Description

To configure the system to prevent the hfsplus kernel module from being loaded, add the following line to the file /etc/modprobe.d/hfsplus.conf:

install hfsplus /bin/true

This effectively prevents usage of this uncommon filesystem.

Rationale

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Remediation

Shell script

The following script can be run on the host to remediate the issue.

#!/bin/bash

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

if LC_ALL=C grep -q -m 1 "^install hfsplus" /etc/modprobe.d/hfsplus.conf ; then
	
	sed -i 's#^install hfsplus.*#install hfsplus /bin/true#g' /etc/modprobe.d/hfsplus.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/hfsplus.conf
	echo "install hfsplus /bin/true" >> /etc/modprobe.d/hfsplus.conf
fi

if ! LC_ALL=C grep -q -m 1 "^blacklist hfsplus$" /etc/modprobe.d/hfsplus.conf ; then
	echo "blacklist hfsplus" >> /etc/modprobe.d/hfsplus.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Ansible playbook

The following playbook can be run with Ansible to remediate the issue.

- name: Ensure kernel module 'hfsplus' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/hfsplus.conf
    regexp: install\s+hfsplus
    line: install hfsplus /bin/true
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_hfsplus_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

- name: Ensure kernel module 'hfsplus' is blacklisted
  lineinfile:
    create: true
    dest: /etc/modprobe.d/hfsplus.conf
    regexp: ^blacklist hfsplus$
    line: blacklist hfsplus
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_hfsplus_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required