Linux Server Hardening: Security Review

OVERVIEW

This sample demonstrates a defensive security and health review for one fictional Ubuntu web server. It focuses on practical risk reduction without exploitation or destructive testing.

THE CHALLENGE

The server hosted a small company website but had accumulated avoidable exposure: password-based SSH access, an unused public database port, manual patching and an untested backup recovery process.

REVIEW SCOPE

Operating-system update and support status

SSH, user, sudo and administrator access

Firewall rules, listening services and exposed ports

Web server and selected TLS settings

Authentication logs and failed-login activity

Backup and recovery readiness

PRIORITIZED FINDINGS

The fictional review identified two high-risk, three medium-risk and two low-risk findings. The highest priorities were administrative access controls and unnecessary public exposure.

APPROVED IMPROVEMENTS

Disabled SSH password login after confirming key access.

Restricted the unused public database port.

Enabled security-only automatic updates.

Added a failed-login alert threshold.

Documented active privileged accounts and owners.

VERIFICATION

Every change was reversible and discussed before implementation. Application health checks passed, a new SSH key session was tested before the original session closed, and rollback steps were documented.

30-DAY ACTION PLAN

The sample handover assigns owners and target dates for a backup restore test, privileged access review, monitoring verification and web security-header deployment.

SAMPLE NOTICE

This is a fictional portfolio demonstration. It shows my review process and reporting quality and is not presented as work completed for a real client.