Attacking APIs

In the previous chapter, we explored the passive and active techniques that can be used to discover APIs. The focus in this chapter moves on to actively attacking and exploiting those APIs using various methods to exploit vulnerabilities in the API design or implementation. By the end of this key chapter of the book, you will be able to attack APIs on your own using various techniques. As a builder of APIs, one of the best ways to test their defense is to attack them yourself.

Secure APIs rely on strong authentication and authorization. In the first topic, we will learn how to attack by identifying design and implementation weaknesses. Fuzzing and brute force attacks are among the easiest to perform, and you will learn how to use automated attacks to crack open an API. Next, the focus turns to data-based attacks: either learning how to trick an API into accepting more data than expected (often leading to injection-based attacks) or finding APIs that leak excessive...