JWT Exploitation for Pentesters

JSON Web Token (JWT) has almost become an industry standard for securing REST APIs, and it is extremely useful for web applications, websites, and API developers as well as AppSec professionals as it helps with authorization and secure information exchange between parties. However, improper JWT implementation and flawed JWT handling can often lead to several vulnerabilities, such as flawed JWT signature verification, allowing the Non-algorithm, algorithm confusion, insecure shared or private keys, and others. This allows attackers to target JWT and bypass access control through several attacks, such as algorithm manipulation, brute-forcing weak secret keys, Key ID (KID) manipulation, parameter injections, and injecting arbitrary or no signatures Learning JWT exploitation helps penetration testers, ethical hackers, and security professionals improve their API and application pentesting skills.

The course will begin with a thorough introduction to JSON Web Tokens, where you’ll learn what exactly JWT is, as well as its importance and applications. You’ll then gain a deeper understanding of JWT, where you’ll explore its components and learn how is it applied and how it works. Moving ahead, you’ll then learn about the common vulnerabilities and attacks that affect JWT. Next, the course will illustrate how to set up the lab for JWT exploitation and how to manually create an RS256 Signature and HS256 Signature. You’ll then perform vulnerability scanning on applications using an open-source tool to find JWT vulnerabilities. Next, the course will shift its focus to performing attacks to gain access and carry out token manipulation. Here, you’ll start by learning how to brute-force secret keys, how to leak secret keys, and how to perform None algorithm Exploitation. The course will also illustrate how to perform weak HMAC algorithm exploitation, how to perform algorithm confusion, and how to inject tokens with Arbitrary Signatures. The course will also demonstrate how to carry out signature stripping attacks and how to perform header manipulation. You’ll then move on to understanding how to perform Key ID Manipulation and Injection attacks, starting with performing Key ID manipulation. This will be followed by an illustration of how to carry out directory traversal with Key ID abuse and how to perform SQL injection with Key ID abuse. You’ll also learn how to perform parameter injection and how to carry out command injection. Next, you’ll explore how to document your findings in a report, while you’ll also learn about a few best practices on how to ensure JWT security. The course will also provide a cheat sheet for JWT security testing. The course will end with a short guide for the learners on how they can further leverage what they learned in this course by pursuing EC-Council Certified Encryption Specialist (E|CES).

By the end of this course, you’ll have all the skills needed to test JWT implementations for Vulnerabilities.