Linux Security Hardening

Linux security hardening is the systematic application of configuration changes, access controls, kernel parameters, and monitoring capabilities to a Linux system to reduce its attack surface and constrain what an adversary can do after gaining initial access.

Security PostureSPHSecurityAdvancedCONFIDENTIAL3,375 words14 min readApr 7, 2026

Last updated Apr 11, 2026

CLASSIFICATION: CONFIDENTIAL

This article requires CONFIDENTIAL clearance or higher.

What you need

Create a free Nexus ID to access CDA proprietary content including PDM domain explainers, methodology deep-dives, and reconnaissance mission briefings.

Create Nexus ID (Free)

Also at this clearance level

Threat IntelligenceTIDThreatIntermediate

Table of Contents

Linux Security Hardening

What you need

Also at this clearance level

APT28 (Fancy Bear / Forest Blizzard)

Lazarus Group (HIDDEN COBRA / Diamond Sleet)

Salt Typhoon

Single Sign-On (SSO) Architecture

The Academy

The Command Post

The Armory