What is SQL Injection and How it Works?

 SQL Injection is a type of cyber attack where an attacker injects malicious SQL code into a vulnerable application's input field, usually a web form, with the intention of manipulating the database behind the application.

The attack works by taking advantage of a vulnerability in the application's code that allows unsanitized user input to be executed as SQL commands by the database.

Here's an example scenario of how SQL injection works:

Let's say there's a web application that has a login form where a user enters their username and password. The application's code uses the following SQL query to authenticate the user:

SELECT * FROM users WHERE username = 'username' AND password = 'password'

An attacker can inject malicious SQL code into the input fields to change the behavior of the query. For example, they can use the following input:

username: ' OR 1=1 --
password: password

The resulting SQL query becomes:

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

The double dash (--) is used to comment out the remaining part of the original SQL query, effectively making the query always return true. As a result, the attacker gains unauthorized access to the application, and potentially the underlying database.

This is just one example of how SQL injection works. There are many variations of the attack that can be used to extract sensitive information, modify or delete data, and even take over the entire system. To prevent SQL injection, developers should always sanitize and validate user input, use parameterized queries or prepared statements, and limit the privileges of database users.