Advanced · 18 lessons

Cyber Security

Cyber security protects websites, servers, and user data from attacks. Hosting security spans SSL encryption, firewalls, malware scanning, access control, and incident response. A single breach can destroy trust and cause legal liability.

Key Concepts

SSL/TLS Encryption Web Application Firewall DDoS Mitigation OWASP Top 10 Two-Factor Auth Backups & Recovery Malware Scanning Security Headers

Key Takeaways

✓ Always use HTTPS — encrypt all data in transit with TLS 1.2+.
✓ Keep software updated — most breaches exploit known vulnerabilities.
✓ Implement WAF rules to block SQL injection, XSS, and bot attacks.
✓ Maintain daily backups stored off-site — test restores regularly.

Lessons in This Topic

Security Fundamentals (CIA Triad)

Confidentiality, Integrity, Availability.

Confidentiality: only authorized users access data (encryption, access control). Integrity: data is not tampered with (checksums, audit logs). Availability: systems stay online (redundancy, DDoS protection). All three must be balanced for effective security.

SSL/TLS & HTTPS Setup

Encrypt connections and verify identity.

TLS certificates prove server identity and encrypt traffic. Free certs from Let's Encrypt via Certbot. Force HTTPS with redirects. Enable HSTS header to prevent downgrade attacks. Use TLS 1.2 minimum; disable SSLv3 and TLS 1.0/1.1.

Common Web Attacks & Defenses

XSS, SQL injection, CSRF, and mitigations.

SQL Injection: use parameterized queries, never concatenate user input. XSS: escape output, use Content-Security-Policy headers. CSRF: use anti-CSRF tokens in forms. Brute force: rate limiting, fail2ban, CAPTCHA. File upload attacks: validate types, store outside web root.

Server Hardening Checklist

Lock down Linux servers step by step.

Disable root SSH login. Use key-based auth only. Configure ufw firewall (allow 22, 80, 443 only). Install fail2ban. Enable automatic security updates. Remove unused services. Set up intrusion detection. Regular vulnerability scans with tools like Lynis.

DDoS Protection Strategies

Survive traffic floods and bot attacks.

Layer 3/4 attacks (SYN floods) mitigated at network level by providers like Cloudflare. Layer 7 attacks (HTTP floods) need WAF and rate limiting. Use CDN to absorb traffic. Implement caching to reduce origin load. Have an incident response plan ready.