# yaml-language-server: $schema=../../../../schema/control.schema.json
id: CB-UBU-SVC-017
title: Keep the cron daemon enabled and running
finding:
  title: The cron daemon is installed but not running
  description: Scheduled maintenance and security jobs, such as log rotation or integrity checks, silently stop.
status: active
profiles: [core]
risk:
  severity: low
assessment: automated
tags: [cron, scheduling]

applicability:
  facts: [cron]

description: |
  `cron` runs the jobs in `/etc/crontab`, `/etc/cron.d/`, the `/etc/cron.hourly` to
  `/etc/cron.monthly` directories and the users' crontabs. When the package is installed,
  `cron.service` must be enabled and running.
rationale: |
  Packages and administrators rely on cron for periodic tasks: integrity checks, report mails,
  cleanup jobs. A stopped daemon disables them without any error message.
impact: |
  None known.
notes: |
  Ubuntu installs and enables cron by default, on servers, desktops and cloud images. The control
  is not applicable only when the package was removed.

audit:
  manual: |
    `systemctl is-enabled cron` must print `enabled` and `systemctl is-active cron` must print
    `active`.
  logic: all
  checks:
    - id: enabled
      engine: systemd-unit
      description: cron is enabled.
      spec: { unit: cron.service, state: enabled }
    - id: active
      engine: shell
      description: cron is running.
      spec:
        script: systemctl is-active cron.service || exit 1

remediation:
  manual: |
    Run `systemctl unmask cron` if it is masked, then `systemctl enable --now cron`.
  effects:
    restart: none
    disruption: none
    lockout_risk: false
  rollback: |
    Run `systemctl disable --now cron`.
  scripts:
    - id: enabled
      from_check: enabled

references:
  - title: cron(8), Ubuntu manual pages
    url: https://manpages.ubuntu.com/manpages/noble/man8/cron.8.html
    publisher: Canonical
    kind: vendor-doc
    accessed: 2026-10-19
  - title: systemctl(1), Ubuntu manual pages
    url: https://manpages.ubuntu.com/manpages/noble/man1/systemctl.1.html
    publisher: Canonical
    kind: vendor-doc
    accessed: 2026-10-19
mappings:
  - framework: nist-800-53r5
    framework_version: "5.1.1"
    id: CM-6
    relation: related
  - framework: cis-ubuntu-2004
    framework_version: "3.0.0"
    id: "2.4.1.1"
    relation: equivalent
  - framework: cis-ubuntu-2204
    framework_version: "3.0.0"
    id: "2.4.1.1"
    relation: equivalent
  - framework: cis-ubuntu-2404
    framework_version: "2.0.0"
    id: "2.4.1.1"
    relation: equivalent
  - framework: cis-ubuntu-2604
    framework_version: "1.0.0"
    id: "2.4.1.1"
    relation: equivalent
related_controls:
  - id: CB-UBU-SVC-018
    type: related

authors:
  - name: Alice
    github: Sn0wAlice
verified:
  - date: 2026-10-19
    by: Sn0wAlice
    versions: ["20.04"]
    environment: Proxmox VM, Ubuntu 20.04 cloud image, kernel 5.4.0-216-generic
    notes: "Passes on the stock image (cron installed and running) and after reboot."
  - date: 2026-10-19
    by: Sn0wAlice
    versions: ["22.04"]
    environment: Proxmox VM, Ubuntu 22.04 cloud image, kernel 5.15.0-198-generic
    notes: "Passes on the stock image (cron installed and running) and after reboot."
  - date: 2026-10-19
    by: Sn0wAlice
    versions: ["24.04"]
    environment: Proxmox VM, Ubuntu 24.04 cloud image, kernel 6.8.0-147-generic
    notes: "Passes on the stock image (cron installed and running) and after reboot."
  - date: 2026-10-19
    by: Sn0wAlice
    versions: ["26.04"]
    environment: Proxmox VM, Ubuntu 26.04 cloud image, kernel 7.0.0-38-generic
    notes: "Passes on the stock image (cron installed and running) and after reboot."
introduced_in: 0.1.0
created: 2026-10-19
updated: 2026-10-19