Security
HTTPS, SQL injection, XSS, DDoS — what can go wrong and how to prevent it.
Why Security Matters
A security breach isn't just embarrassing—it's costly. Data breaches average $4.5 million in costs. Stolen customer data ruins trust. Ransomware can take your entire business offline. Security must be part of every decision: what languages you choose, how you store data, who can access what.
HTTPS: Encryption in Transit
HTTP transmits data in plain text. Anyone between you and the server can see it. HTTPS (HTTP Secure) encrypts the connection using TLS (Transport Layer Security), ensuring that intercepted data is unreadable.
- SSL/TLS: The encryption protocol that secures data in transit. Every website must use it.
- Let's Encrypt: Free certificate authority. Eliminated the excuse "HTTPS is too expensive." Use it.
- Mixed Content: Never load images or scripts over HTTP if your page is HTTPS. Browsers block it.
The OWASP Top 10: Common Web Vulnerabilities
OWASP publishes the top 10 most critical web application security risks. Here's a simplified version:
1. SQL Injection
Attacker enters SQL code into a form, which runs on your database. Example: entering `' OR '1'='1` into a login form might bypass authentication.
SELECT * FROM users WHERE email = 'admin@example.com' OR '1'='1';
Prevention: Always use parameterized queries / prepared statements. Never concatenate user input into SQL.
2. Broken Authentication
Weak password policies, session tokens that are predictable, or stolen credentials allow attackers to impersonate users.
Prevention: Force strong passwords, use multi-factor authentication (MFA), use secure session management, rate-limit login attempts.
3. Sensitive Data Exposure
Storing or transmitting sensitive data (passwords, API keys, credit cards) insecurely. Hardcoding secrets in code or storing them in plain text.
Prevention: Encrypt sensitive data at rest, use HTTPS, never hardcode secrets, use environment variables and secret management tools.
4. Security Misconfiguration
Leaving default passwords, exposing debug information, unnecessary services running, or missing security headers.
Prevention: Apply security updates, disable unnecessary features, use security headers (Content-Security-Policy, X-Frame-Options), audit configurations.
5. Cross-Site Scripting (XSS)
Attacker injects malicious JavaScript into your site, which runs in users' browsers. Could steal session tokens or credentials.
Prevention: Sanitize user input, use Content Security Policy headers, escape output, use frameworks that auto-escape by default.
6. DDoS Attacks
Attacker floods your server with traffic, overwhelming it and making your site inaccessible to real users.
Prevention: Use a DDoS mitigation service (Cloudflare, AWS Shield), rate-limiting, and caching to absorb traffic spikes.
7–10. Other Critical Issues
- CSRF: Attacker tricks users into making unwanted requests. Prevention: CSRF tokens.
- XXE: XML External Entity attacks. Prevention: disable XML features if not needed.
- Insecure Deserialization: Untrusted data deserialization can execute code. Prevention: avoid deserializing untrusted data.
- Using Components with Known Vulnerabilities: Prevention: keep dependencies updated, use tools like Dependabot.
WordPress Security: Special Considerations
WordPress powers 43% of all websites, making it a giant target. Its prevalence and extensibility create unique risks:
- Plugin/Theme Vulnerabilities: Third-party plugins are often poorly maintained and security-audited. Every plugin is a potential attack surface.
- Weak Admin Passwords: WordPress brute-force attacks are constant. Use strong passwords and MFA plugins.
- Outdated Core: WordPress updates include security patches. Delay = vulnerability.
WordPress Prevention Checklist: Keep core, plugins, and themes updated. Use a security plugin (Wordfence, iThemes Security). Use strong passwords + MFA. Limit login attempts. Regular backups. Managed WordPress hosting (WP Engine, Kinsta) handles many of these automatically.