Web Application Security Guide: Defending Against XSS, CSRF & SQL Injection

Security must be integrated at every tier of application development, from browser headers to database queries and cryptographic key management.

1. Preventing SQL Injection with Prepared Statements

Never concatenate user input directly into SQL strings. Always utilize parameterized queries via PDO in PHP or Entity Framework Core in .NET.

2. CSRF & SameSite Cookies

Protecting state-modifying requests with cryptographic anti-forgery tokens and setting SameSite=Lax or SameSite=Strict on session cookies.