Linux Server Hardening Checklist

Linux Server Hardening Checklist – Secure Your Infrastructure Before Attackers Do!

Linux servers power most of today’s cloud, DevOps, and enterprise environments. But leaving them with default settings can expose your infrastructure to serious security risks.
Here is a 14-Point Linux Server Hardening Checklist every system administrator and security professional should follow:

✅ 1. Keep System Updated:  Regularly update OS packages and security patches.
✅ 2. Disable Root Login:  Prevent direct root SSH login to reduce attack surface.
✅ 3. Use Strong Password Policies:  Enforce complexity, expiration, and lockout rules.
✅ 4. Configure SSH Security:  Change default SSH port, disable password auth, and use key-based authentication.
✅ 5. Enable Firewall (UFW / iptables / firewalld):  Allow only necessary ports and services.
✅ 6. Install Intrusion Detection Systems (IDS):  Use tools like Fail2Ban, AIDE, or OSSEC.
✅ 7. Disable Unnecessary Services:  Remove or disable unused applications and daemons.
✅ 8. Implement Least Privilege Access:  Grant only required permissions to users and services.
✅ 9. Secure File Permissions:  Audit and restrict access to sensitive system files.
✅ 10. Enable Logging & Monitoring:  Use syslog, auditd, or centralized monitoring solutions.
✅ 11. Configure Automatic Security Updates:  Reduce risk of vulnerabilities with unattended upgrades.
✅ 12. Protect Against Brute Force Attacks:  Deploy Fail2Ban or similar tools.
✅ 13. Encrypt Data & Backup Regularly:  Use disk encryption and maintain secure backups.
✅ 14. Perform Regular Security Audits & Scans:  Use tools like Lynis, OpenSCAP, or Nessus.