Skip to content

Require Authentication for Single User Mode

An XCCDF Rule

Description

Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup.

By default, single-user mode is protected by requiring a password and is set in /usr/lib/systemd/system/rescue.service.

Rationale

This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.

ID
xccdf_org.ssgproject.content_rule_require_singleuser_auth
Severity
Medium
References
Updated



Remediation - Ansible

- name: Require single user mode password
  lineinfile:
    create: true
    dest: /usr/lib/systemd/system/rescue.service
    regexp: ^#?ExecStart=
    line: ExecStart=-/bin/sh -c "/usr/sbin/sulogin; /usr/bin/systemctl --fail --no-block

Remediation - Shell Script

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

service_file="/usr/lib/systemd/system/rescue.service"

sulogin='/bin/sh -c "/usr/sbin/sulogin; /usr/bin/systemctl --fail --no-block default"'