What is SQL injection, and how to prevent it?

SQL injection is a type of attack that allows attackers to execute malicious SQL statements on a database. Here is a step-by-step example of how an SQL injection attack might work:

Step 1: Find a vulnerable input field

The attacker starts by looking for input fields on a website that are vulnerable to SQL injection attacks. This might include search boxes, login forms, or any other field that takes user input and sends it to the server.

For example, consider a website with a search box that allows users to search for products in a database:

<form action="/search" method="get">
  <input type="text" name="query">
  <button type="submit">Search</button>
</form>

Step 2: Inject a malicious SQL statement

Once the attacker has identified a vulnerable input field, they can try injecting a malicious SQL statement into the field. The statement might be designed to bypass authentication, retrieve sensitive data, or modify the database in some way.

For example, an attacker might try injecting the following SQL statement into the search box:

'; DELETE FROM products WHERE 1=1; --

This statement would cause the database to delete all rows from the products table, effectively destroying the data.