Web Security Fundamentals

Security should be a priority from day one. This guide covers essential concepts every developer should know.

The OWASP Top 10

Understanding common vulnerabilities:

• Injection attacks (SQL, XSS, Command)
• Broken authentication and session management
• Sensitive data exposure without encryption

Attack Vectors

Common Vulnerabilities

1. SQL Injection
2. Cross-Site Scripting (XSS)
3. Cross-Site Request Forgery (CSRF)
   • Token-based prevention
   • SameSite cookies
4. Insecure Direct Object References

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1// Example: Preventing SQL Injection
2// BAD - Vulnerable to injection
3const query = `SELECT * FROM users WHERE id = ${userId}`;
4
5// GOOD - Parameterized query
6const query = "SELECT * FROM users WHERE id = ?";
7db.query(query, [userId]);

Security Headers

"Security is not a product, but a process."

• Bruce Schneier

Defense in Depth

Multiple layers of protection:

• Input validation on both client and server
• Output encoding for XSS prevention
• Trust user input Always sanitize and validate

OWASP is the definitive resource for web security!