SQL Injection: Protecting Your Application from Attacks

SQL injection poses a significant threat to database-driven applications that rely on SQL queries. The vulnerability lies in the lack of input sanitization, which allows attackers to manipulate the queries’ behavior.

Let’s take a look at a simple Node.js example to understand how SQL injection can occur:

const color = // coming from user input
const query = `SELECT * FROM cars WHERE color = '${color}'`

In this case, if the value of color is a legitimate color like “red” or “blue”, the query works as intended. However, let’s consider what happens when an attacker provides the following string as input: "blue'; DROP TABLE cars;".

The value of query would then become:

SELECT * FROM cars WHERE color = 'blue'; DROP TABLE cars;'

Executing this query can have catastrophic consequences, wiping out all the data if the user’s database permission allows dropping tables.

Here’s another scenario to demonstrate how SQL injection can wreak havoc:

const query = 'SELECT * FROM users WHERE name = "' + name + '"'

Assuming the name variable is collected from a form input without proper sanitization, an attacker could enter the following value: "flavio"; DELETE * FROM users; SELECT * FROM users WHERE name ="flavio".

Now, the query would transform into:

SELECT * FROM users WHERE name = "flavio"; DELETE * FROM users; SELECT * FROM users WHERE name ="flavio"

This would result in the complete deletion of the users table.

To prevent SQL injection attacks, ensure proper input sanitization, escape quotes, and utilize a robust Object Relational Mapper (ORM) like Prisma, Sequelize for JavaScript, or Eloquent for Laravel. These tools help protect your application by handling SQL queries securely.