# yaml-language-server: $schema=../../../../schema/control.schema.json
id: CB-UBU-AUDIT-002
title: Forward the journal to rsyslog only when rsyslog is the chosen logger
finding:
  title: The journal forwarding setting does not match the logging system in use
  description: Messages are either sent to a syslog daemon that does not exist, or not given to the rsyslog daemon that is supposed to store and forward them.
status: active
profiles: [core]
risk:
  severity: low
assessment: automated
tags: [journald, rsyslog, logging]

description: |
  An Ubuntu system should use one logging system: the systemd journal alone, or the journal
  feeding rsyslog, which then writes text files and forwards messages. The journald setting
  `ForwardToSyslog=` decides whether each message is also handed to a syslog daemon.

  - When the `rsyslog` package is installed, `ForwardToSyslog=yes` is required, so that rsyslog
    receives every message.
  - When it is not installed, `ForwardToSyslog=no` is required, since nothing reads the
    forwarded messages.
rationale: |
  A mismatch either loses messages in the files and remote copies managed by rsyslog, or wastes
  resources on a socket nobody reads. Choosing one system keeps the log pipeline simple to review.
impact: |
  None known. The journal keeps every message in both cases.
notes: |
  Ubuntu Server installs rsyslog by default. On Ubuntu 20.04 and 22.04, journald is built with
  `ForwardToSyslog=yes` as its default (shown commented out in `/etc/systemd/journald.conf`); from
  24.04 the built-in default is `no` and the rsyslog package ships
  `/usr/lib/systemd/journald.conf.d/syslog.conf` with `ForwardToSyslog=yes`. The check takes the
  built-in default into account when no file sets the value. The fix writes
  `/etc/systemd/journald.conf.d/syslog.conf`, which replaces the file shipped by rsyslog.

setting:
  location: /etc/systemd/journald.conf.d/syslog.conf
  default_value: yes (rsyslog installed by default)
  recommended_value: yes when rsyslog is installed, no otherwise

audit:
  manual: |
    1. Run `dpkg-query -W -f='${Status}\n' rsyslog` to know whether rsyslog is installed.
    2. Run `systemd-analyze cat-config systemd/journald.conf`. The last `ForwardToSyslog=` must be
       `yes` if rsyslog is installed, and `no` (or absent) otherwise.
  checks:
    - id: forward
      engine: shell
      description: Effective ForwardToSyslog= compared with the presence of rsyslog.
      spec:
        script: |
          v=$(systemd-analyze cat-config systemd/journald.conf 2>/dev/null | sed -n 's/^[[:space:]]*ForwardToSyslog=//p' | tail -n 1)
          # unset: the build default, shown commented out in journald.conf (yes on 20.04 and 22.04)
          [ -n "$v" ] || v=$(sed -n 's/^#ForwardToSyslog=//p' /etc/systemd/journald.conf 2>/dev/null | head -n 1)
          case ${v:-no} in yes | true | on | 1) v=yes ;; *) v=no ;; esac
          case $(dpkg-query -W -f='${Status}' rsyslog 2>/dev/null) in
            *' installed') want=yes ;;
            *) want=no ;;
          esac
          echo "ForwardToSyslog=$v, expected $want"
          [ "$v" = "$want" ]

remediation:
  manual: |
    Create `/etc/systemd/journald.conf.d/syslog.conf` with `[Journal]` and `ForwardToSyslog=yes` if
    rsyslog is installed, `ForwardToSyslog=no` otherwise, then run `systemctl restart systemd-journald`.
  effects:
    restart: service
    services: [systemd-journald]
    disruption: none
    lockout_risk: false
  rollback: |
    Delete `/etc/systemd/journald.conf.d/syslog.conf` and run `systemctl restart systemd-journald`.
  scripts:
    - id: dropin
      engine: shell
      content: |
        case $(dpkg-query -W -f='${Status}' rsyslog 2>/dev/null) in
          *' installed') v=yes ;;
          *) v=no ;;
        esac
        f=/etc/systemd/journald.conf.d/syslog.conf
        mkdir -p /etc/systemd/journald.conf.d
        cb_backup "$f"
        printf '%s\n' '# Written by CIRSEC Baselines CB-UBU-AUDIT-002' '[Journal]' "ForwardToSyslog=$v" >"$f"
        chmod 644 "$f"

references:
  - title: journald.conf(5), Ubuntu manual pages
    url: https://manpages.ubuntu.com/manpages/noble/man5/journald.conf.5.html
    publisher: Canonical
    kind: vendor-doc
    accessed: 2026-10-19
  - title: rsyslogd(8), Ubuntu manual pages
    url: https://manpages.ubuntu.com/manpages/noble/man8/rsyslogd.8.html
    publisher: Canonical
    kind: vendor-doc
    accessed: 2026-10-19
mappings:
  - framework: anssi-linux
    framework_version: "2.0"
    id: R71
    relation: related
  - framework: nist-800-53r5
    framework_version: "5.1.1"
    id: AU-6(4)
    relation: related
  - framework: cis-ubuntu-2004
    framework_version: "3.0.0"
    id: "6.2.2.2"
    relation: partial
    note: CIS asks for no when journald is the only logger; ours asks for yes when rsyslog is installed (Ubuntu default) and no otherwise.
  - framework: cis-ubuntu-2004
    framework_version: "3.0.0"
    id: "6.2.3.3"
    relation: stricter
    note: Ours also turns forwarding off when rsyslog is absent.
  - framework: cis-ubuntu-2204
    framework_version: "3.0.0"
    id: "6.1.1.1.4"
    relation: partial
    note: CIS asks for no when journald is the only logger; ours asks for yes when rsyslog is installed (Ubuntu default) and no otherwise.
  - framework: cis-ubuntu-2204
    framework_version: "3.0.0"
    id: "6.1.2.3"
    relation: stricter
    note: Ours also turns forwarding off when rsyslog is absent.
  - framework: cis-ubuntu-2404
    framework_version: "2.0.0"
    id: "6.1.1.1.3"
    relation: stricter
    note: Ours also turns forwarding off when rsyslog is absent.
  - framework: cis-ubuntu-2604
    framework_version: "1.0.0"
    id: "6.1.1.1.3"
    relation: stricter
    note: Ours also turns forwarding off when rsyslog is absent.
threats:
  - framework: cwe
    id: CWE-778
related_controls:
  - id: CB-UBU-AUDIT-001
    type: related
  - id: CB-UBU-AUDIT-005
    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: "rsyslog installed, built-in default ForwardToSyslog=yes: passes on stock image (check reads the commented build default)."
  - 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 stock image (built-in default yes, rsyslog installed); after removing rsyslog fails, fix writes ForwardToSyslog=no and passes."
  - 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 stock image (rsyslog ships journald.conf.d/syslog.conf with ForwardToSyslog=yes); kept 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 stock image (rsyslog ships journald.conf.d/syslog.conf with ForwardToSyslog=yes); kept after reboot."
introduced_in: 0.1.0
created: 2026-10-19
updated: 2026-10-19