Lynis Deep Dive¶

Platform: Linux | Binary: lynis | Type: Unix/Linux security auditor

Overview¶

Lynis is a battle-tested security auditing tool for Unix/Linux systems. It performs an extensive health scan of your systems to support system hardening and compliance testing.

How CISentinel Uses Lynis¶

1. Scan Execution¶

lynis audit system --no-colors --quiet --quick 2>&1

CISentinel runs Lynis in non-interactive, non-colored mode and captures both stdout and the log file.

2. Output Capture¶

Lynis produces two key artifacts: - stdout: Human-readable audit output with findings - report-data file: Machine-parseable .dat file with structured findings

3. Result Parsing¶

CISentinel's parser reads the Lynis .dat file to extract: - Hardening index (0-100 score) - Individual test results - Suggestions and warnings - Severity levels mapped to CISentinel's standard schema

Installation per Distro¶

Verification¶

lynis --version

CISentinel uses the verify_cmd configuration to ensure Lynis is functional after installation.

Output Artifacts¶

Hardening Index¶

Lynis produces a Hardening Index — a score from 0-100 representing the overall security posture:

Key Features Tested¶

Lynis tests hundreds of items including: - Boot and authentication - Kernel hardening - Memory and process restrictions - Software packages and updates - Networking and firewalls - SSH configuration - File permissions and integrity - Logging and auditing - Cryptography settings - Malware detection

Common Issues¶