Details

Single user mode (rescue mode) is used for recovery when the system detects an issue during boot or by manual selection from the bootloader.

Rationale:

Requiring authentication in single user mode (rescue mode) prevents an unauthorized user from rebooting the system into single user to gain root privileges without credentials.

Solution

Edit /usr/lib/systemd/system/rescue.service and /usr/lib/systemd/system/emergency.service and set ExecStart to use /sbin/sulogin or /usr/sbin/sulogin:

ExecStart=-/bin/sh -c ‘/sbin/sulogin; /usr/bin/systemctl –fail –no-block default’

Notes:

The systemctl option –fail is synonymous with –job-mode=fail . Using either is acceptable.

This Benchmark recommendation maps to:

Red Hat Enterprise Linux 7 Security Technical Implementation Guide:

Version 2, Release: 3 Benchmark Date: 26 Apr 2019

Vul ID: V-77823

Rule ID: SV-92519r2_rule

STIG ID: RHEL-07-010481

Severity: CAT II

Supportive Information

The following resource is also helpful.

• https://workbench.cisecurity.org/files/2688

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system Unix.

References

• 800-53|CM-6
• CSCv7|5.1

Source

• Tenable.com/audits