pentester.land· Oct 18, 2023· by Tommaso Innocenti (@innotommy), Matteo Golinelli, Kaan Onarlioglu, Ali Mirheidari, Bruno Crispo, Engin Kirda

OAuth 2.0 Redirect URI Validation Falls Short, Literally

Target Program: Atlassian, Meta / Facebook, GitHub, Microsoft, Yahoo! / Verizon Media, LinkedIn, Slack, VK, LINE, AuthDigital (Naver), OK, ORCID

🎯 Vulnerability: OAuth 2.0 / JWT Authentication Bypass

💡 Defense Fix: Strictly verify JWT signatures on the backend, enforce state parameter validation, and reject 'alg: none'.

#OAuth#Path confusion#Open redirect#HTTP parameter pollution#Account takeover