Project Overview

I was tasked with the challenge of reviving a critical, 9-year-old virtual router system written in legacy PHP. The initial request was simple: get it running. However, my initial audit revealed the system was a significant security and operational risk. I took the initiative to not just revive it, but to completely re-engineer its foundation for the modern era.

Security Audit and Remediation

My first step was a comprehensive security audit of the legacy codebase. I discovered and remediated numerous critical vulnerabilities, including:

• Direct susceptibility to SQL injection attacks due to unsanitised inputs.
• Hardcoded database credentials and sensitive API keys committed directly into the codebase.
• Outdated dependencies with known public exploits.

I systematically patched these flaws, used .env files for all secrets, and updated all dependencies to secure, stable versions.

Modernisation and Containerisation

To solve the system’s brittleness and complex manual deployment process, I containerised the entire application using Docker and Docker Compose. This involved:

• Creating separate, optimised Docker images for the PHP application, the database, and other services.
• Writing a streamlined docker-compose.yml file that transformed the deployment into a single, reliable command.
• This approach eliminated environment inconsistencies and dramatically simplified future maintenance and deployments.

Infrastructure Management

The final challenge was deploying the modernised application onto the client’s infrastructure, which was running an end-of-life version of Ubuntu (16.04 LTS). I successfully managed a high-stakes, in-place server upgrade to Ubuntu 24.04 LTS, navigating and resolving all resulting package dependency conflicts to ensure a stable host environment for the new containerised system.

Outcome

What began as a simple revival task became a full-scale modernisation project. The result was a system that was not only functional but also secure, stable, and maintainable for the foreseeable future. I transformed a high-risk legacy asset into a reliable, modern service.