In today’s digital landscape, web applications handle a vast amount of data, often receiving inputs from users through forms, search boxes, APIs, and more. However, when these inputs aren’t properly validated or sanitized, they can serve as entry points for attackers, allowing them to inject malicious code into the system. This type of attack is known as **injection** and remains one of the most dangerous and prevalent security threats.

In this chapter, we will explore the different types of injection attacks, how they occur, and the serious risks they pose to applications and organizations. From manipulating databases to executing unauthorized system commands, injection vulnerabilities can compromise sensitive data, disrupt services, and in severe cases, lead to full control of a server.

By understanding the mechanics of these attacks and how untrusted data can alter the behavior of applications, developers and security professionals can better protect their systems. Let’s dive into the world of injection vulnerabilities and learn how they are exploited, setting the stage for understanding how to defend against them.