# yaml-language-server: $schema=../../../../schema/control.schema.json
id: CB-DEB-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: |
  A Debian 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: |
  Debian 13 ships `/usr/lib/systemd/journald.conf.d/syslog.conf` with `ForwardToSyslog=yes`, even
  when no syslog daemon is installed. The fix writes `/etc/systemd/journald.conf.d/syslog.conf`,
  which replaces that vendor file. On Debian 12 the default is `no`.

setting:
  location: /etc/systemd/journald.conf.d/syslog.conf
  default_value: "Debian 12: no; Debian 13: yes"
  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)
          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 "$f"
        printf '%s\n' '# Written by CIRSEC Baselines CB-DEB-AUDIT-002' '[Journal]' "ForwardToSyslog=$v" >"$f"
        chmod 644 "$f"

references:
  - title: journald.conf(5), Debian manual pages
    url: https://manpages.debian.org/trixie/systemd/journald.conf.5.en.html
    publisher: Debian
    kind: vendor-doc
    accessed: 2026-10-18
  - title: rsyslogd(8), Debian manual pages
    url: https://manpages.debian.org/trixie/rsyslog/rsyslogd.8.en.html
    publisher: Debian
    kind: vendor-doc
    accessed: 2026-10-18
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-debian-12
    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-debian-13
    framework_version: "1.1.0"
    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-DEB-AUDIT-001
    type: related
  - id: CB-DEB-AUDIT-005
    type: related

authors:
  - name: Alice
    github: Sn0wAlice
verified:
  - date: 2026-10-18
    by: Sn0wAlice
    versions: ["12"]
    environment: Proxmox VM, Debian 12 genericcloud image, kernel 6.1.0-54-cloud-amd64, BIOS boot
    notes: "Passes on fresh install (no rsyslog, default no); after installing rsyslog fails, fix writes ForwardToSyslog=yes and passes."
  - date: 2026-10-18
    by: Sn0wAlice
    versions: ["13"]
    environment: Proxmox VM, Debian 13 genericcloud image, kernel 6.12.113+deb13-cloud-amd64, BIOS boot
    notes: "Fails on fresh install (vendor syslog.conf sets yes without rsyslog); fix masks it with no; with rsyslog installed the fix sets yes."
introduced_in: 0.1.0
created: 2026-10-18
updated: 2026-10-18