What Is SQL Injection and How to Prevent It?

SQL injection (SQLi) has topped the OWASP Top 10 vulnerability list for over a decade. After spending years conducting security audits and penetration tests, I’ve witnessed firsthand how this seemingly simple vulnerability can completely compromise web applications. Despite being well-understood, SQL injection continues to plague production systems—I discovered critical SQLi vulnerabilities in enterprise applications as recently as 2024. This guide explains how SQL injection works, how attackers exploit it, and most importantly, how to prevent it.