Browser extensions are often underestimated in the context of application security. Yet, these tiny tools wield significant power. Whether they’re used for productivity, tracking, debugging, or communication, extensions can access and manipulate content on nearly every site a user visits. When organizations publish their own extensions — either for internal utility or for customers — they potentially expose an overlooked attack surface ripe for recon.

In this article, we will explore how ethical hackers and bug bounty hunters can perform effective reconnaissance on browser extensions owned by target companies. We’ll look at tools, techniques, real-world examples, and vulnerabilities to watch out for. If you’re looking to take your recon game to the next level, this guide will light the way.

Most organizations focus heavily on their web apps and APIs. But what about their browser extensions? These components often:

• Communicate with internal APIs.