SV-281307r1268241: RHEL 10 must prevent the loading of a new kernel for later execution. | Red Hat Enterprise Linux 10 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 10 must prevent the loading of a new kernel for later execution.

Description

Discussion Text

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and has been provided by a trusted vendor. Disabling kexec_load prevents an unsigned kernel image (that could be a windows kernel or modified vulnerable kernel) from being loaded. Kexec can be used to subvert the entire secureboot process and should be avoided at all costs, especially because it can load unsigned kernel images.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-003992

References

DPMS Target Red Hat Enterprise Linux 10 DISA DPMS Target Red Hat Enterprise Linux 10 5733

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.stig.rhel10os:def:281307
# RHEL 10 must prevent the loading of a new kernel for later execution.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# kernel.kexec_load_disabled = 1
# sysctl_object (sysctl_test)
test_1() {
  [ "$(cat /proc/sys/kernel/kexec_load_disabled)" -eq 1 ]
}

if test_1; then
  echo "PASS"
else
  echo "FAIL"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# OVAL Definition: oval:mil.disa.stig.rhel10os:def:281307

if [ ! -f "/proc/sys/kernel/kexec_load_disabled" ]; then
    echo "FAIL"
    exit 1
fi

value=$(cat /proc/sys/kernel/kexec_load_disabled)
if [ "$value" != "1" ]; then
    echo "FAIL"
    exit 1
fi

echo "PASS"
exit 0

Remediation

Configure RHEL 10 to disable kernel image loading.

Create a drop-in if it does not already exist:

$ sudo vi /etc/sysctl.d/99-kernel_kexec_load_disabled.conf

Add the following to the file:

kernel.kexec_load_disabled = 1

Reload settings from all system configuration files with the following command:

$ sudo sysctl --system