SV-274003r1198253: Amazon Linux 2023 must restrict exposed kernel pointer addresses access. | Amazon Linux 2023 STIG SCAP Benchmark

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Assessment Title

Rule Text

Amazon Linux 2023 must restrict exposed kernel pointer addresses access.

Description

Discussion Text

Exposing kernel pointers (through procfs or "seq_printf()") exposes kernel writeable structures, which may contain functions pointers. If a write vulnerability occurs in the kernel, allowing write access to any of this structure, the kernel can be compromised. This option disallows any program without the CAP_SYSLOG capability to get the addresses of kernel pointers by replacing them with "0". Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192

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

IA Controls

NIST SP 800-53

Not mappedCCI-001082Not mappedCCI-002824

References

DPMS Target Amazon Linux 2023 DISA DPMS Target Amazon Linux 2023 5700

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.amzlx23os:def:274003
# Amazon Linux 2023 must restrict exposed kernel pointer addresses access.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# kernel.kptr_restrict is set to 1
# sysctl_object (sysctl_test)
test_1() {
  [ "$(cat /proc/sys/kernel/kptr_restrict)" -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:mil.disa.stig.amzlx23os:def:274003
if [ ! -f /etc/sysctl.d/00-default.conf ]; then echo "PASS"; exit 0; fi
if [ ! -f /etc/sysctl.d/99-sysctl-local.conf ]; then echo "PASS"; exit 0; fi
if grep -q "^kernel.kptr_restrict = 1$" /etc/sysctl.d/99-sysctl-local.conf; then echo "PASS"; exit 0; fi
echo "FAIL"; exit 1

Remediation

Configure Amazon Linux 2023 to restrict exposed kernel pointer addresses access. 

Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory:

kernel.kptr_restrict = 1

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

$ sudo sysctl --system