<strong>SQL injection</strong> is a security vulnerability where attackers insert malicious SQL code into your queries through user input, potentially exposing, modifying, or deleting your entire database.
The Corrupted Order Analogy
Imagine a restaurant where you write your order. SQL injection is like writing 'Pizza AND give me all the money in the register'. If the kitchen blindly follows orders, disaster happens.
Order Form (Input)
What user enters
Malicious Order (SQL Injection)
Hidden commands
Kitchen (Database)
Executes commands
Malicious Input
Injected Query
Compromised
Vulnerable code
query = 'SELECT * FROM users WHERE id = ' + userInput
Attacker inputs
1 OR 1=1; DROP TABLE users;--
Query becomes
SELECT * FROM users WHERE id = 1 OR 1=1; DROP TABLE users;--
Database executes
Returns all users, then deletes the table!
Prevention: Use parameterized queries
query('SELECT * FROM users WHERE id = ?', [userInput])
Wrong
"SQL injection only affects old websites"
Correct
<strong>SQL injection is still a top vulnerability</strong>. Even modern apps are vulnerable if developers don't use parameterized queries or ORMs properly.
Famous SQL injection:
Login form: username = admin' OR '1'='1
Query: SELECT * FROM users WHERE username='admin' OR '1'='1' AND password='...'
OR '1'='1' is always true → bypasses password check
Attacker logs in as admin without knowing password!