Disable D-Bus IPC Service (messagebus)

An XCCDF Rule

Description

D-Bus provides an IPC mechanism used by a growing list of programs, such as those used for Gnome, Bluetooth, and Avahi. Due to these dependencies, disabling D-Bus may not be practical for many systems. The messagebus service can be disabled with the following command:

$ sudo systemctl mask --now messagebus.service

Rationale

If no services which require D-Bus are needed, then it can be disabled. As a broker for IPC between processes of different privilege levels, it could be a target for attack. However, disabling D-Bus is likely to be impractical for any system which needs to provide a graphical login session.

ID: xccdf_org.ssgproject.content_rule_service_messagebus_disabled
Severity: Low
References: 11 14 3 9

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

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: over 1 year ago

Remediation Templates

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

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

include disable_messagebus
class disable_messagebus {
  service {'messagebus':
    enable => false,
    ensure => 'stopped',
  }
}

- name: Block Disable service messagebus
  block:
  - name: Disable service messagebus
    block:

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

    - name: Intentionally ignored previous 'Disable service messagebus' failure, service
        was already disabled
      meta: noop
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  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
  - low_severity
  - no_reboot_needed
  - service_messagebus_disabled

- name: Unit Socket Exists - messagebus.socket
  command: systemctl -q list-unit-files messagebus.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"]
  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
  - low_severity
  - no_reboot_needed
  - service_messagebus_disabled

- name: Disable socket messagebus
  systemd:
    name: messagebus.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - socket_file_exists.stdout_lines is search("messagebus.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
  - low_severity
  - no_reboot_needed
  - service_messagebus_disabled

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'messagebus.service'
"$SYSTEMCTL_EXEC" disable 'messagebus.service'
"$SYSTEMCTL_EXEC" mask 'messagebus.service'# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files messagebus.socket; then
    "$SYSTEMCTL_EXEC" stop 'messagebus.socket'
    "$SYSTEMCTL_EXEC" mask 'messagebus.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 'messagebus.service' || true

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

Disable D-Bus IPC Service (messagebus)

Description

Rationale

Remediation Templates

A Kubernetes Patch

OS Build Blueprint

A Puppet Snippet

An Ansible Snippet

A Shell Script