Verify nftables Service is Disabled

An XCCDF Rule

Description

nftables is a subsystem of the Linux kernel providing filtering and classification of network packets/datagrams/frames and is the successor to iptables. The nftables service can be disabled with the following command:

systemctl disable nftables

Rationale

Running both firewalld and nftables may lead to conflict. nftables is actually one of the backends for firewalld management tools.

ID: xccdf_org.ssgproject.content_rule_service_nftables_disabled
Severity: Medium
References: 1.2 1.2.1
Updated: 5 days ago

include disable_nftables

class disable_nftables {
  service {'nftables':
    enable => false,
    ensure => 'stopped',  }
}

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.1  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_nftables_disabled

- name: Verify nftables Service is Disabled - Collect systemd Services Present in
    the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: ( "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
    and "kernel" in ansible_facts.packages )
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.1
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_nftables_disabled

- name: Verify nftables Service is Disabled - Ensure nftables.service is Masked
  ansible.builtin.systemd:
    name: nftables.service
    state: stopped
    enabled: false
    masked: true
  when:
  - ( "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
    and "kernel" in ansible_facts.packages )
  - service_exists.stdout_lines is search("nftables.service", multiline=True)
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.1
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_nftables_disabled

- name: Unit Socket Exists - nftables.socket
  ansible.builtin.command: systemctl -q list-unit-files nftables.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: ( "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
    and "kernel" in ansible_facts.packages )
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.1
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_nftables_disabled

- name: Verify nftables Service is Disabled - Disable Socket nftables
  ansible.builtin.systemd:
    name: nftables.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - ( "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
    and "kernel" in ansible_facts.packages )
  - socket_file_exists.stdout_lines is search("nftables.socket", multiline=True)
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.1
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_nftables_disabled


[customizations.services]
masked = ["nftables"]

# Remediation is applicable only in certain platforms
if ( rpm --quiet -q firewalld && rpm --quiet -q nftables && rpm --quiet -q kernel ); then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'nftables.service'
"$SYSTEMCTL_EXEC" disable 'nftables.service'"$SYSTEMCTL_EXEC" mask 'nftables.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files nftables.socket; then
    "$SYSTEMCTL_EXEC" stop 'nftables.socket'
    "$SYSTEMCTL_EXEC" mask 'nftables.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'nftables.service' || true

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

Verify nftables Service is Disabled

Description

Rationale

Remediation - Puppet

Remediation - Ansible

Remediation - OS Build Blueprint

Remediation - Shell Script