How do I harden Linux servers with CIS Benchmarks?

More context

The highest-impact areas in most Linux benchmarks are SSH configuration (key-based authentication, protocol restrictions, root login), removal of unnecessary services and packages, kernel network parameters, and audit logging via auditd. Test remediation in staging first: some Level 2 controls, and a few Level 1 controls in unusual environments, can affect applications.

One-time hardening decays: package updates, troubleshooting sessions, and configuration management changes all reintroduce drift. CISGuard scans Linux estates continuously against the CIS benchmarks, alerts on drift, and maps results to NIST 800-53, ISO 27001, and SOC 2, and it deploys on-premises or air-gapped where servers cannot reach a SaaS scanner.