{
  "id": "CB-UBU-AUTH-022",
  "standard": "ubuntu",
  "version": "main",
  "url": "https://baselines.cirsec.org/b/ubuntu/CB-UBU-AUTH-022",
  "json": "https://baselines.cirsec.org/b/ubuntu/CB-UBU-AUTH-022.json",
  "yaml": "https://baselines.cirsec.org/b/ubuntu/CB-UBU-AUTH-022.yml",
  "profiles_effective": [
    "server-hardened"
  ],
  "license": "Text CC BY 4.0, code Apache-2.0",
  "attribution": "CIRSEC Baselines, https://baselines.cirsec.org",
  "control": {
    "id": "CB-UBU-AUTH-022",
    "title": "Disable reboot with Ctrl-Alt-Del on the console",
    "finding": {
      "title": "Anyone at the console can reboot the system with Ctrl-Alt-Del",
      "description": "A reboot without logging in interrupts services and can be the first step of a boot-time attack."
    },
    "status": "active",
    "profiles": [
      "server-hardened"
    ],
    "risk": {
      "severity": "low"
    },
    "assessment": "automated",
    "tags": [
      "console",
      "physical-access",
      "systemd"
    ],
    "description": "systemd reboots the system when Ctrl-Alt-Del is pressed on a text console, through\n`ctrl-alt-del.target`. Masking that target turns the key combination into a no-op.\n",
    "rationale": "On a server, a reboot should always be a deliberate, authenticated action. The key combination\nis reachable without logging in from a physical keyboard, a KVM switch or a hypervisor console,\nsometimes by accident.\n",
    "impact": "Ctrl-Alt-Del no longer reboots the system from a text console. Administrators reboot with\n`systemctl reboot`.\n",
    "notes": "Desktops handle the key combination in the graphical session; see the desktop controls.\n",
    "audit": {
      "manual": "Run `systemctl is-enabled ctrl-alt-del.target`. It must print `masked`.\n",
      "checks": [
        {
          "id": "masked",
          "engine": "systemd-unit",
          "spec": {
            "unit": "ctrl-alt-del.target",
            "state": "masked"
          }
        }
      ]
    },
    "remediation": {
      "manual": "Run `systemctl mask ctrl-alt-del.target` and `systemctl daemon-reload`.\n",
      "effects": {
        "restart": "none",
        "disruption": "none",
        "lockout_risk": false
      },
      "rollback": "Run `systemctl unmask ctrl-alt-del.target`.\n",
      "scripts": [
        {
          "id": "mask",
          "from_check": "masked"
        }
      ]
    },
    "references": [
      {
        "title": "systemd.special(7), Ubuntu manual pages (ctrl-alt-del.target)",
        "url": "https://manpages.ubuntu.com/manpages/noble/man7/systemd.special.7.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"
      }
    ],
    "threats": [
      {
        "framework": "mitre-attack",
        "id": "T1529"
      }
    ],
    "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 a fresh install; generated fix masks the target, check again and second fix idempotent; profile server-hardened, not rebooted after this fix."
      },
      {
        "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 a fresh install; generated fix masks the target, check again and second fix idempotent; profile server-hardened, not rebooted after this fix."
      },
      {
        "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 a fresh install; generated fix masks the target, check again and second fix idempotent; profile server-hardened, not rebooted after this fix."
      },
      {
        "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 a fresh install; generated fix masks the target, check again and second fix idempotent; profile server-hardened, not rebooted after this fix."
      }
    ],
    "introduced_in": "0.1.0",
    "created": "2026-10-19",
    "updated": "2026-10-19"
  }
}