# yaml-language-server: $schema=../../../../schema/control.schema.json
id: CB-DEB-SVC-026
title: Disable the kdump kernel crash dump service
finding:
  title: Kernel crash dumps are collected on the system
  description: A crash dump is a copy of memory that can hold keys, passwords and sensitive data.
status: active
profiles: [server-hardened]
risk:
  severity: low
assessment: automated
tags: [services, kdump, kernel, data-exposure]

description: |
  `kdump-tools` loads a capture kernel at boot (`kdump-tools.service`). When the main kernel
  crashes, the capture kernel saves its memory to `/var/crash`.

  The control passes when `kdump-tools.service` is masked or not installed at all.
rationale: |
  The dump holds everything that was in memory: secrets of running services, session keys,
  documents. It stays on disk after the reboot and can be copied by anyone who gets access to
  `/var/crash` or to backups. Kernel crash analysis is rarely needed in production.
impact: |
  Kernel crashes leave no dump to analyse. The memory reserved by the `crashkernel=` boot
  parameter stays reserved until the parameter is removed (`apt purge kdump-tools`, then
  `update-grub` and a reboot).
notes: |
  `kdump-tools` is not installed by default. Systems where kernel developers or support need
  dumps should exclude this control in their tailoring file and protect `/var/crash` instead.

audit:
  manual: |
    Run `systemctl is-enabled kdump-tools.service`. It must print `masked`, or fail because the unit
    does not exist.
  checks:
    - id: kdump-tools
      engine: systemd-unit
      description: kdump capture kernel loader.
      spec: { unit: kdump-tools.service, state: masked }

remediation:
  manual: |
    Run `systemctl mask --now kdump-tools.service`. To also free the reserved memory, run
    `apt purge kdump-tools`, then `update-grub`, and reboot.
  effects:
    restart: none
    disruption: none
    lockout_risk: false
  rollback: |
    Run `systemctl unmask kdump-tools.service` then `systemctl enable --now kdump-tools.service`.
  scripts:
    - id: kdump-tools
      from_check: kdump-tools

references:
  - title: kdump-tools(5), Debian manual pages
    url: https://manpages.debian.org/trixie/kdump-tools/kdump-tools.5.en.html
    publisher: Debian
    kind: vendor-doc
    accessed: 2026-10-18
  - title: kdump-config(8), Debian manual pages
    url: https://manpages.debian.org/trixie/kdump-tools/kdump-config.8.en.html
    publisher: Debian
    kind: vendor-doc
    accessed: 2026-10-18
  - title: ANSSI-BP-028 v2.0 - Recommandations de configuration d'un système GNU/Linux (R62)
    url: https://messervices.cyber.gouv.fr/documents-guides/fr_np_linux_configuration-v2.0.pdf
    publisher: ANSSI
    kind: guide
    accessed: 2026-10-18
mappings:
  - framework: anssi-linux
    framework_version: "2.0"
    id: R62
    relation: partial
    note: R62 asks to disable every unneeded service; this control covers kdump.
  - framework: nist-800-53r5
    framework_version: "5.1.1"
    id: CM-7
    relation: partial
threats:
  - framework: mitre-attack
    id: T1003
  - framework: cwe
    id: CWE-528

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
    notes: "Fresh image passes; with kdump-tools installed the check fails, fix masks the service, audit passes after reboot; kdump-tools still purges cleanly."
  - date: 2026-10-18
    by: Sn0wAlice
    versions: ["13"]
    environment: Proxmox VM, Debian 13 genericcloud image, kernel 6.12.113+deb13-cloud-amd64
    notes: "Fresh image passes; with kdump-tools installed the check fails, fix masks the service, audit passes after reboot; kdump-tools still purges cleanly."
introduced_in: 0.1.0
created: 2026-10-18
updated: 2026-10-18