Disable xinetd Service

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Description

The xinetd service can be disabled with the following command:

$ sudo systemctl mask --now xinetd.service

Rationale

The xinetd service provides a dedicated listener service for some programs, which is no longer necessary for commonly-used network services. Disabling it ensures that these uncommon services are not running, and also prevents attacks against xinetd itself.

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 dpkg-query --show --showformat='${db:Status-Status}' 'linux-base' 2>/dev/null | grep -q '^installed$'; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
if [[ $("$SYSTEMCTL_EXEC" is-system-running) != "offline" ]]; then
  "$SYSTEMCTL_EXEC" stop 'xinetd.service'
fi
"$SYSTEMCTL_EXEC" disable 'xinetd.service'
"$SYSTEMCTL_EXEC" mask 'xinetd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files xinetd.socket; then
    if [[ $("$SYSTEMCTL_EXEC" is-system-running) != "offline" ]]; then
      "$SYSTEMCTL_EXEC" stop 'xinetd.socket'
    fi
    "$SYSTEMCTL_EXEC" mask 'xinetd.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 'xinetd.service' || true

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: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.7
  - 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_xinetd_disabled

- name: Disable xinetd Service - Disable service xinetd
  block:

  - name: Disable xinetd 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

  - name: Disable xinetd Service - Ensure xinetd.service is Masked
    ansible.builtin.systemd:
      name: xinetd.service
      state: stopped
      enabled: false
      masked: true
    when: service_exists.stdout_lines is search("xinetd.service", multiline=True)

  - name: Unit Socket Exists - xinetd.socket
    ansible.builtin.command: systemctl -q list-unit-files xinetd.socket
    register: socket_file_exists
    changed_when: false
    failed_when: socket_file_exists.rc not in [0, 1]
    check_mode: false

  - name: Disable xinetd Service - Disable Socket xinetd
    ansible.builtin.systemd:
      name: xinetd.socket
      enabled: false
      state: stopped
      masked: true
    when: socket_file_exists.stdout_lines is search("xinetd.socket", multiline=True)
  tags:
  - NIST-800-171-3.4.7
  - 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_xinetd_disabled
  - special_service_block
  when: '"linux-base" in ansible_facts.packages'