SV-217283r958928: The SUSE operating system must implement kptr-restrict to prevent the leaking of internal kernel addresses. | SUSE Linux Enterprise Server 12 STIG SCAP Benchmark

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Assessment Title

Rule Text

The SUSE operating system must implement kptr-restrict to prevent the leaking of internal kernel addresses.

Description

Discussion Text

Some adversaries launch attacks with the intent of executing code in nonexecutable regions of memory or in memory locations that are prohibited. Security safeguards employed to protect memory include, for example, data execution prevention and address space layout randomization. Data execution prevention safeguards can either be hardware-enforced or software-enforced, with hardware providing the greater strength of mechanism. Examples of attacks are buffer overflow attacks.

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

IA Controls

NIST SP 800-53

Not mappedCCI-002824SV-92175V-77479

References

DPMS Target SUSE Linux Enterprise Server 12 DISA DPMS Target SUSE Linux Enterprise Server 12 4033

Checks

DISA STIG (Manual Reference)

Verify the SUSE operating system prevents leaking of internal kernel addresses.

Check that the SUSE operating system prevents leaking of internal kernel addresses by running the following command:

> sudo sysctl kernel.kptr_restrict
kernel.kptr_restrict = 1

If the kernel parameter "kptr_restrict" is not equal to "1" or nothing is returned, this is a finding.

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.sles12os:def:217283
# The SUSE operating system must implement kptr-restrict to prevent the leaking of internal kernel addresses.
# 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
# DISA STIG / SCAP compliance check for kernel.kptr_restrict: oval:mil.disa.stig.sles12os:def:217283
if [ -x /usr/sbin/sysctl ]; then sysctl -qn kernel.kptr_restrict | grep -q '^kernel.kptr_restrict\s*1$' ] || { echo "FAIL"; exit 1; }; echo "PASS"; exit 0; else echo "FAIL"; exit 1; fi

Remediation

Configure the SUSE operating system to prevent leaking of internal kernel addresses by running the following command: 

> sudo sysctl -w kernel.kptr_restrict=1

If "1" is not the system's default value, add or update the following line in "/etc/sysctl.d/99-stig.conf":

> sudo sh -c 'echo "kernel.kptr_restrict=1" >> /etc/sysctl.d/99-stig.conf'

> sudo sysctl --system