Disable DHCP Service

An XCCDF Rule

Description

The dhcpd service should be disabled on any system that does not need to act as a DHCP server. The dhcpd service can be disabled with the following command:

$ sudo systemctl mask --now dhcpd.service

Rationale

Unmanaged or unintentionally activated DHCP servers may provide faulty information to clients, interfering with the operation of a legitimate site DHCP server if there is one.

ID: xccdf_org.ssgproject.content_rule_service_dhcpd_disabled
Severity: Medium
References: 11 14 3 9

BAI10.01 BAI10.02 BAI10.03 BAI10.05 DSS05.02 DSS05.05 DSS06.06

CCI-000366

4.3.3.5.1 4.3.3.5.2 4.3.3.5.3 4.3.3.5.4 4.3.3.5.5 4.3.3.5.6 4.3.3.5.7 4.3.3.5.8 4.3.3.6.1 4.3.3.6.2 4.3.3.6.3 4.3.3.6.4 4.3.3.6.5 4.3.3.6.6 4.3.3.6.7 4.3.3.6.8 4.3.3.6.9 4.3.3.7.1 4.3.3.7.2 4.3.3.7.3 4.3.3.7.4 4.3.4.3.2 4.3.4.3.3

SR 1.1 SR 1.10 SR 1.11 SR 1.12 SR 1.13 SR 1.2 SR 1.3 SR 1.4 SR 1.5 SR 1.6 SR 1.7 SR 1.8 SR 1.9 SR 2.1 SR 2.2 SR 2.3 SR 2.4 SR 2.5 SR 2.6 SR 2.7 SR 7.6

A.12.1.2 A.12.5.1 A.12.6.2 A.14.2.2 A.14.2.3 A.14.2.4 A.9.1.2

CM-6(a) CM-7(a) CM-7(b)

PR.IP-1 PR.PT-3
Updated: 5 days ago

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

include disable_dhcpd

class disable_dhcpd {
  service {'dhcpd':
    enable => false,
    ensure => 'stopped',  }
}

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_dhcpd_disabled

- name: Disable DHCP Service - 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: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_dhcpd_disabled

- name: Disable DHCP Service - Ensure dhcpd.service is Masked
  ansible.builtin.systemd:
    name: dhcpd.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("dhcpd.service", multiline=True)
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_dhcpd_disabled

- name: Unit Socket Exists - dhcpd.socket
  ansible.builtin.command: systemctl -q list-unit-files dhcpd.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_dhcpd_disabled

- name: Disable DHCP Service - Disable Socket dhcpd
  ansible.builtin.systemd:
    name: dhcpd.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("dhcpd.socket", multiline=True)
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_dhcpd_disabled


service disable dhcpd


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

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'dhcpd.service'
"$SYSTEMCTL_EXEC" disable 'dhcpd.service'"$SYSTEMCTL_EXEC" mask 'dhcpd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files dhcpd.socket; then
    "$SYSTEMCTL_EXEC" stop 'dhcpd.socket'
    "$SYSTEMCTL_EXEC" mask 'dhcpd.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 'dhcpd.service' || true

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

Disable DHCP Service

Description

Rationale

Remediation - Kubernetes Patch

Remediation - Puppet

Remediation - Ansible

Remediation - script:kickstart

Remediation - OS Build Blueprint

Remediation - Shell Script