Discovering APIs

In the previous chapter, we explored the foundations of attacking APIs, focusing on many of the tools that attackers use. In this chapter, we’ll use these skills to learn how to discover APIs in the real world. We will learn how to discover APIs using passive methods (where we do not interact with the API directly) and active methods (where we interact with the API directly). We will also learn how to find details of how the API is implemented and how to use this knowledge to attack an API.

For an API defender, it is important to understand the techniques used by your adversaries in discovering your APIs so that you can implement defensive measures to prevent easy discovery and further analysis. In particular, defenders should pay attention to attackers’ techniques in identifying implementation details and use this knowledge to harden their implementations.

For an API attacker, a thorough reconnaissance process provides useful information about...