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

3.4.1.2
Updated: about 1 year ago


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

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

- name: Block Disable service nftables
  block:

  - name: Disable service nftables
    block:

    - name: Disable service nftables
      systemd:
        name: nftables.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
    rescue:

    - name: Intentionally ignored previous 'Disable service nftables' failure, service
        was already disabled
      meta: noop
  when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
    "container"] and "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
    )
  tags:
  - 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
  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: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
    "container"] and "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
    )
  tags:
  - PCI-DSSv4-1.2.1
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_nftables_disabled

- name: Disable socket nftables
  systemd:
    name: nftables.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
  - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
    and "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
    )
  - socket_file_exists.stdout_lines is search("nftables.socket",multiline=True)
  tags:
  - PCI-DSSv4-1.2.1
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_nftables_disabled

# Remediation is applicable only in certain platforms
if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q firewalld && rpm --quiet -q nftables ); 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

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0    systemd:
      units:
      - name: nftables.service
        enabled: false
        mask: true
      - name: nftables.socket
        enabled: false
        mask: true

include disable_nftables

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

Verify nftables Service is Disabled

Description

Rationale

Remediation - OS Build Blueprint

Remediation - Ansible

Remediation - Shell Script

Remediation - Kubernetes Patch

Remediation - Puppet