Kernel Hardening on Root Lock by HeartSuite

Kernel Hardening Comparison Matrix

Mon, 01 Jan 0001 00:00:00 +0000

Subject: Root Lock by HeartSuite, kernel 5.19.6
Config SHA-256: d67caa637263c33ce939b7eef867f0695d60d11d285d6694a7f5567e73ba6fbc
Tool: kernel-hardening-checker commit b9b83a0, run 2026-05-19
Source file: evidence-pack-5.19.6.txt

Part 1 — Measured comparison (same kernel era)

All three configs below are built from the 5.19.x kernel tree. Checker scores are directly comparable — same Kconfig namespace, same option universe.

Config	Source	Kernel	Overall	Attack-surface	Exploit-resistance
HS 5.19.6	HS canonical config (SHA256: `d67caa6…`)	5.19.6	129/258 (50.0%)	91/132 (68.9%)	31/109 (28.4%)
Arch linux-hardened	gitlab.archlinux.org/archlinux/packaging/packages/linux-hardened @ tag `5.19.11.hardened1-1`	5.19.11	158/258 (61.2%)	77/132 (58.3%)	69/109 (63.3%)
Vanilla x86_64 defconfig	Bundled in kernel-hardening-checker	5.17.1	126/258 (48.8%)	90/132 (68.2%)	29/109 (26.6%)

Reading the table

Attack-surface measures how many dangerous kernel features are disabled. Higher = more things turned off.
Exploit-resistance measures how many defensive mitigations against memory bugs are enabled. Higher = harder to exploit.
These two axes are largely independent and optimized for different threat models.

What this shows

HS leads on attack-surface (91 vs 77 vs 90): it disables BPF_SYSCALL, FUSE_FS, OVERLAY_FS, SECURITY_APPARMOR, SECURITY_TOMOYO, and USER_NS — all of which Arch linux-hardened keeps enabled for its general-purpose user base.

Security Auditor Brief: Kernel Hardening Posture

Mon, 01 Jan 0001 00:00:00 +0000

Subject: Root Lock by HeartSuite, kernel 5.19.6
Config SHA-256: d67caa637263c33ce939b7eef867f0695d60d11d285d6694a7f5567e73ba6fbc
Measured: 2026-05-19 using kernel-hardening-checker commit b9b83a0
Full data: kernel-comparison-matrix-5.19.6.md, evidence-pack-5.19.6.txt

Threat Model

HeartSuite’s kernel hardening targets one specific threat: a process on the protected system attempting to bypass the kernel module’s VFS-level enforcement. The design choice is to remove the kernel features that make bypass possible, rather than to harden the kernel against general exploitation.

What the measurements show

Attack-surface reduction

Automated score: 91/132 (68.9%)
Reference points (era-matched, same 5.19.x kernel generation): Arch linux-hardened 5.19.11: 77/132 (58.3%). Vanilla upstream defconfig 5.17: 90/132 (68.2%). KSPP target (6.17, version-agnostic intent): 131/132 (99.2%).

Procurement Brief: Kernel Hardening at a Glance

Mon, 01 Jan 0001 00:00:00 +0000

Subject: Root Lock by HeartSuite, kernel 5.19.6
Measured: 2026-05-19 using kernel-hardening-checker, an independent open-source tool
Full technical data: kernel-comparison-matrix-5.19.6.md

What this document covers

Every Linux kernel ships with hundreds of configuration choices that determine how easy it is to exploit vulnerabilities or escape security controls. This document compares HeartSuite’s kernel choices to a directly comparable community-hardened kernel and the KSPP industry benchmark.

All numbers on this page are outputs of the same measurement tool applied identically to each kernel configuration. No estimates. The Arch linux-hardened comparison uses the 5.19.11 release — the same kernel generation as HeartSuite 5.19.6, making scores directly comparable.

LSM Comparison: HeartSuite vs SELinux, AppArmor, and TOMOYO

Mon, 01 Jan 0001 00:00:00 +0000

Subject: Root Lock by HeartSuite, kernel 5.19.6
Audience: Security engineers familiar with SELinux, AppArmor, or TOMOYO evaluating HeartSuite for containment or appliance deployments.

The core distinction

SELinux, AppArmor, and TOMOYO all answer the same question: given that a kernel feature is present, what should a process be allowed to do with it?

HeartSuite answers a different question: which kernel features should exist on this system at all?

This is not a claim that one approach is universally superior. For single-purpose containment appliances, removing bypass primitives from the kernel is more reliable than writing policy around them — because policy can be misconfigured, and because certain primitives (BPF, FUSE, overlayfs) can defeat any MAC policy regardless of how carefully it is written.

Analyst Summary: HeartSuite Kernel Hardening

Mon, 01 Jan 0001 00:00:00 +0000

Kernel: Root Lock by HeartSuite 5.19.6. Config hash: d67caa637263c33ce939b7eef867f0695d60d11d285d6694a7f5567e73ba6fbc. Measured: 2026-05-19.

HeartSuite’s Linux kernel contains just 9 loadable modules — compared to 3,500 to 4,000 in a standard Debian Linux system. This isn’t because the system is less capable; it’s because the kernel was built for one job and nothing else was included.

The approach extends beyond raw module count. HeartSuite disables specific kernel features that security researchers have identified as the most common paths for bypassing security controls: BPF (a programmable kernel interface), FUSE (user-space filesystems), overlay filesystems, and all competing security policy engines including AppArmor and SELinux. Each of these has been used in documented real-world attacks to escape software sandboxes or override security policies.