# yaml-language-server: $schema=../../../../schema/control.schema.json
id: CB-UBU-AUDIT-032
title: Install the AIDE file integrity checker
finding:
  title: No file integrity checker is installed
  description: Changes to system binaries and configuration files, such as a replaced program or a planted backdoor, go unnoticed.
status: active
profiles: [core]
risk:
  severity: medium
assessment: automated
tags: [aide, integrity]

description: |
  AIDE (Advanced Intrusion Detection Environment) records the checksums and attributes of
  system files in a database, then compares the files with it. Ubuntu splits it into `aide`
  (the program) and `aide-common` (configuration in `/etc/aide/`, `aideinit`, daily check).
  Neither is installed by default.
rationale: |
  An integrity checker is the simplest way to detect that files which should never change
  (binaries, libraries, configuration) have been modified, whether by an intruder or by mistake.
impact: |
  Installing AIDE alone does nothing until its database is built (CB-UBU-AUDIT-034).
notes: |
  The fix installs without recommended packages: `aide` recommends a mail transport agent, which
  `apt-get` would otherwise install (exim4). Reports of the daily check are written to
  `/var/log/aide/`; install and configure a mail transport if they must be mailed.

setting:
  location: aide and aide-common packages
  default_value: Not installed
  recommended_value: Installed

audit:
  manual: |
    Run `dpkg-query -W -f='${Package} ${Status}\n' aide aide-common`. Both must end with `installed`.
  checks:
    - id: aide
      engine: package
      description: aide is installed.
      spec: { name: aide, state: installed }
    - id: aide-common
      engine: package
      description: aide-common is installed.
      spec: { name: aide-common, state: installed }

remediation:
  manual: |
    Run `apt-get install --no-install-recommends aide aide-common`.
  effects:
    restart: none
    disruption: none
    lockout_risk: false
  rollback: |
    Run `apt-get purge aide aide-common`.
  scripts:
    - id: install
      engine: shell
      content: |
        DEBIAN_FRONTEND=noninteractive apt-get -o DPkg::Lock::Timeout=300 install -y -q --no-install-recommends aide aide-common

references:
  - title: aide(1), Ubuntu manual pages
    url: https://manpages.ubuntu.com/manpages/noble/man1/aide.1.html
    publisher: Canonical
    kind: vendor-doc
    accessed: 2026-10-19
  - title: ANSSI-BP-028 v2.0 - Recommandations de configuration d'un système GNU/Linux (R76)
    url: https://messervices.cyber.gouv.fr/documents-guides/fr_np_linux_configuration-v2.0.pdf
    publisher: ANSSI
    kind: guide
    accessed: 2026-10-19
mappings:
  - framework: anssi-linux
    framework_version: "2.0"
    id: R76
    relation: partial
    note: R76 asks to seal files and check them; this control installs the tool, CB-UBU-AUDIT-034 builds and checks the seals.
  - framework: nist-800-53r5
    framework_version: "5.1.1"
    id: SI-7
    relation: related
  - framework: cis-ubuntu-2004
    framework_version: "3.0.0"
    id: "6.1.1"
    relation: partial
    note: The database initialisation is in CB-UBU-AUDIT-034.
  - framework: cis-ubuntu-2204
    framework_version: "3.0.0"
    id: "6.3.1"
    relation: partial
    note: The database initialisation is in CB-UBU-AUDIT-034.
  - framework: cis-ubuntu-2404
    framework_version: "2.0.0"
    id: "6.3.1"
    relation: partial
    note: The database initialisation is in CB-UBU-AUDIT-034.
  - framework: cis-ubuntu-2604
    framework_version: "1.0.0"
    id: "6.3.1"
    relation: partial
    note: The database initialisation is in CB-UBU-AUDIT-034.
threats:
  - framework: mitre-attack
    id: T1036.005
  - framework: cwe
    id: CWE-353
related_controls:
  - id: CB-UBU-AUDIT-034
    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: "Fails on stock image; fix installs AIDE 0.16.1 without recommends; passes 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: "Fails on stock image; fix installs AIDE 0.17.4 without recommends; passes 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: "Fails on stock image; fix installs AIDE 0.18.6 without recommends; passes 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: "Fails on stock image; fix installs AIDE 0.19.2 without recommends; passes after reboot."
introduced_in: 0.1.0
created: 2026-10-19
updated: 2026-10-19