SQL Injection Explained with Real Attack Scenarios

A login page.

Username. Password. Submit.

Simple, right?

But behind the scenes, the application runs a query like this:

SELECT * FROM users WHERE username='admin' AND password='1234';

Now imagine someone enters this instead:

' OR '1'='1

Suddenly, the system doesn’t check passwords anymore.

It just lets them in.

Welcome to SQL Injection.

What is SQL Injection?

SQL Injection is a vulnerability where attackers manipulate database queries by injecting malicious SQL code.

How It Works

1. User input is inserted into SQL query
2. No validation or sanitization
3. Attacker modifies query logic
4. Database executes malicious command

Real Attack ScenarioLogin bypass:

SELECT * FROM users WHERE username='' OR '1'='1' -- ' AND password='';

👉 This always returns TRUE
👉 Attacker logs in as admin

Advanced Exploitation

Attackers can:

• Dump entire database
  
• Delete tables
  
• Modify data
  
• Gain full control
  

Prevention

• Prepared statements
  
• Parameterized queries
  
• ORM frameworks
  
• Input validation