Understanding Web Security

Web applications face numerous security threats. Understanding attack vectors and implementing defense-in-depth strategies is crucial for protecting user data and maintaining trust.

OWASP Top 10 Vulnerabilities

Rank Vulnerability Prevention
A01 Broken Access Control RBAC, least privilege, deny by default
A02 Cryptographic Failures Strong encryption, TLS 1.3, secure key storage
A03 Injection Parameterized queries, input validation
A04 Insecure Design Threat modeling, secure design patterns
A05 Security Misconfiguration Hardening guides, automated scanning
A06 Vulnerable Components Dependency scanning, regular updates
A07 Authentication Failures MFA, strong password policies, rate limiting
A08 Integrity Failures CI/CD security, signed commits
A09 Logging Failures Centralized logging, monitoring
A10 SSRF Input validation, allowlist URLs

Security Headers Implementation

# Nginx security headers
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
add_header X-Frame-Options "SAMEORIGIN" always;
add_header X-Content-Type-Options "nosniff" always;
add_header X-XSS-Protection "1; mode=block" always;
add_header Content-Security-Policy "default-src 'self'" always;

SQL Injection Prevention

# Vulnerable code - DON'T DO THIS
cursor.execute(f"SELECT * FROM users WHERE email = '{email}'")

# Safe code - parameterized query
cursor.execute("SELECT * FROM users WHERE email = %s", (email,))

Authentication Best Practices

Implement MFA, use bcrypt for password hashing (work factor 12+), implement account lockout after failed attempts, use secure session management with HTTP-only cookies, and implement proper logout functionality.