SQL Injection and Parameterized Queries
Eliminate injection risks by always using prepared statements with PDO.
What is SQL Injection?
SQL injection occurs when user-supplied data is embedded directly in a SQL query, allowing attackers to manipulate the query to access, modify, or delete data.
Classic Example
Concatenating user input into SQL:
<?php
// VULNERABLE: attacker enters username = "' OR '1'='1"
$sql = "SELECT * FROM users WHERE username = '".$_GET["username"]."'";
// Becomes: SELECT * FROM users WHERE username = '' OR '1'='1'
// Returns ALL users!All lessons in this course
- Cross-Site Scripting (XSS) Prevention
- SQL Injection and Parameterized Queries
- CSRF Protection
- Secure Password Storage