How to Prevent SQL Injection

SQL injections remain one of the most dangerous and widespread web application vulnerabilities. If not addressed, they can allow attackers to access, modify, or destroy sensitive data through poorly written database queries. That’s why understanding how to prevent SQL injection—and applying proactive SQL injection testting—is essential for every development and DevSecOps team today.

A recent ScienceDirect study revealed that **24.6% of real-world attacks still involve SQL injection **flaws, proving how persistent and impactful this threat remains.

In this guide, we’ll cover:

What SQL injections are and how they work
OWASP-recommended prevention techniques
Key SQL injection testting strategies
How Xygeni’s SAST engine detects SQL injection vulnerabilities early in the SDLC

Let’s dive into how to secure your code, shift security left, and defend your software supply chain from one of the oldest (and still active) attack methods.

What Is SQL Injection?

SQL Injection is a code-level attack where malicious input is inserted into SQL queries to manipulate or bypass database operations. It often occurs when user-supplied data is used in a query without proper validation or sanitization.

For example, attackers can exploit login forms, search bars, or API parameters to:

Bypass authentication
Retrieve sensitive data
Delete or corrupt records
Execute admin operations in the database**

If you want to prevent SQL injections, the first step is understanding how they work.

Real-World SQL Injection Example

Take a simple Java login query:

String query = "SELECT * FROM users WHERE username = '" + user + "' AND password = '" + pass + "'";

If a user inputs this:

user: ' OR 1=1 --
pass: anything

It becomes:

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

The attacker gains access by making the condition always true. This is a textbook example of why SQL injection testting is so critical during development.