CyberSec Intro: Securing Your Infrastructure

Security isn’t optional. Every exposed service is a target. Here’s what I’ve learned protecting production systems.

The Basics

• Principle of Least Privilege — give minimum access needed
• Defense in Depth — multiple layers, never rely on one control
• Zero Trust — verify everything, trust nothing by default

Quick Wins

1. SSH keys only (disable password auth)
2. Firewall everything, allowlist what’s needed
3. Automatic security updates (unattended-upgrades)
4. Fail2ban for brute force protection
5. TLS everywhere (Let’s Encrypt is free)

Tools Worth Knowing

• nmap — network scanning and service discovery
• Wireshark — packet analysis
• Burp Suite — web app security testing
• OSSEC/Wazuh — host-based intrusion detection
• Trivy — container vulnerability scanning

Mindset

Think like an attacker. Every feature you ship is attack surface. Every dependency is a supply chain risk. Build with paranoia, ship with confidence.