VPS Security Audits Using Lynis

Updated: 28 September 2026 · Applies to: Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9 (Lynis 3.1)

Lynis is a free security auditing tool. It checks hundreds of settings (SSH, firewall, updates, file permissions, services) and gives a hardening score with concrete suggestions. The current version is 3.1.7; it works on Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9.

Install

dnf install epel-release && dnf install lynis     # AlmaLinux / Rocky
apt install lynis                                   # Ubuntu / Debian (may be an older version)

For the newest version on any system, run it straight from its Git repository (no installation needed):

git clone https://github.com/CISOfy/lynis /opt/lynis
cd /opt/lynis && ./lynis audit system

Run an audit

lynis audit system

Read the results

• Warnings: fix these first.
• Suggestions: hardening ideas. Not all fit every server; decide one by one.
• Hardening index: a score out of 100. Use it to track progress, not as a goal in itself.
• Details for one test: lynis show details SSH-7408 (use the test ID from the output). The full report is in /var/log/lynis-report.dat and the log in /var/log/lynis.log.

Typical quick wins

• Disable SSH password login once key login works (PasswordAuthentication no).
• Enable automatic security updates (dnf-automatic or unattended-upgrades).
• Remove services and packages you do not use.

Tip: Run Lynis again after changes, and monthly after that, to catch configuration drift.