SV-281335r1167155: RHEL 10 must disable access to the network bpf system call from nonprivileged processes. | Red Hat Enterprise Linux 10 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 10 must disable access to the network bpf system call from nonprivileged processes.

Description

Discussion Text

Loading and accessing the packet filters programs and maps using the bpf() system call has the potential to reveal sensitive information about the kernel state.

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

IA Controls

NIST SP 800-53

Not mappedCCI-001082

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:281335
# RHEL 10 must disable access to the network bpf system call from nonprivileged processes.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# kernel.unprivileged_bpf_disabled setting in kernel is '1'.
# sysctl_object (sysctl_test)
test_1() {
  [ "$(cat /proc/sys/kernel/unprivileged_bpf_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
# DISA STIG RHEL 10 must disable access to the network bpf system call from nonprivileged processes (oval:mil.disa.stig.rhel10os:def:281335)

if ! command -v sysctl >/dev/null; then
    echo "FAIL"
    exit 1
fi

if [ ! -f "/etc/sysctl.d/99-kernel_unprivileged_bpf_disabled" ]; then
    echo "PASS"
    exit 0
fi

if grep -q "^kernel.unprivileged_bpf_disabled = 1$" /etc/sysctl.d/99-kernel_unprivileged_bpf_disabled; then
    echo "PASS"
    exit 0
fi

echo "FAIL"
exit 1

Remediation

Configure RHEL 10 to prevent privilege escalation through the kernel by disabling access to the bpf system call.

Create the drop-in file if it does not already exist:

$ sudo vi /etc/sysctl.d/99-kernel_unprivileged_bpf_disabled

Add the following line to the file:

kernel.unprivileged_bpf_disabled = 1

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

$ sudo sysctl --system