Disable Ctrl-Alt-Del Burst Action

An XCCDF Rule

Description

By default, SystemD will reboot the system if the Ctrl-Alt-Del key sequence is pressed Ctrl-Alt-Delete more than 7 times in 2 seconds.

To configure the system to ignore the CtrlAltDelBurstAction setting, add or modify the following to /etc/systemd/system.conf:

CtrlAltDelBurstAction=none

Rationale

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

ID: xccdf_org.ssgproject.content_rule_disable_ctrlaltdel_burstaction
Severity: High
References: 12 13 14 15 16 18 3 5

APO01.06 DSS05.04 DSS05.07 DSS06.02

3.4.5

CCI-000366

164.308(a)(1)(ii)(B) 164.308(a)(7)(i) 164.308(a)(7)(ii)(A) 164.310(a)(1) 164.310(a)(2)(i) 164.310(a)(2)(ii) 164.310(a)(2)(iii) 164.310(b) 164.310(c) 164.310(d)(1) 164.310(d)(2)(iii)

4.3.3.7.3

SR 2.1 SR 5.2

A.10.1.1 A.11.1.4 A.11.1.5 A.11.2.1 A.13.1.1 A.13.1.3 A.13.2.1 A.13.2.3 A.13.2.4 A.14.1.2 A.14.1.3 A.6.1.2 A.7.1.1 A.7.1.2 A.7.3.1 A.8.2.2 A.8.2.3 A.9.1.1 A.9.1.2 A.9.2.3 A.9.4.1 A.9.4.4 A.9.4.5

CIP-003-8 R5.1.1 CIP-003-8 R5.3 CIP-004-6 R2.3 CIP-007-3 R2.1 CIP-007-3 R2.2 CIP-007-3 R2.3 CIP-007-3 R5.1 CIP-007-3 R5.1.1 CIP-007-3 R5.1.2

AC-6(1) CM-6(a) CM-6(a)

PR.AC-4 PR.DS-5

FAU_GEN.1.2

SRG-OS-000324-GPOS-00125 SRG-OS-000480-GPOS-00227
Updated: about 1 year ago

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(a)
  - disable_ctrlaltdel_burstaction
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

- name: Disable Ctrl-Alt-Del Burst Action
  lineinfile:
    dest: /etc/systemd/system.conf
    state: present
    regexp: ^CtrlAltDelBurstAction
    line: CtrlAltDelBurstAction=none
    create: true
  when:
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - '"systemd" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(a)
  - disable_ctrlaltdel_burstaction
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { dpkg-query --show --showformat='${db:Status-Status}\n' 'systemd' 2>/dev/null | grep -q installed; }; then

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^CtrlAltDelBurstAction=")
# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "none"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^CtrlAltDelBurstAction=\\>" "/etc/systemd/system.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^CtrlAltDelBurstAction=\\>.*/$escaped_formatted_output/gi" "/etc/systemd/system.conf"
else
    if [[ -s "/etc/systemd/system.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/systemd/system.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/systemd/system.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/systemd/system.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Disable Ctrl-Alt-Del Burst Action

Description

Rationale

Remediation - Ansible

Remediation - Shell Script