Skill UI

This skill demonstrates how to exploit JWT algorithm confusion vulnerabilities. It targets APIs that do not strictly enforce the cryptographic algorithm (alg) specified in the token header. Techniques covered include downgrading from asymmetric algorithms (RS256) to symmetric ones (HS256) using the public key as the secret, performing alg:none bypasses, and manipulating key identifiers (kid, jku, x5u) to achieve authentication bypass and token forgery.

This expert playbook provides comprehensive techniques for testing Cross-Site Request Forgery (CSRF) vulnerabilities in web applications. It covers identifying state-changing endpoints, bypassing anti-CSRF tokens (including missing validation and predictable tokens), and exploiting modern weaknesses like SameSite=Lax via GET methods or misconfigured JSON APIs. Essential reading for security professionals and penetration testers.