This is a guest blogpost by Lauritz Holtmann. He wrote his master thesis:
"Single Sign-On Security: Security Analysis of real-life OpenID Connect Implementations"
Lauritz summarizes his exciting results in the following. The thesis was supervised by Vladislav Mladenov, Christian Mainka, and Jörg Schwenk. You can read find his full thesis here.
OpenID Connect 1.0 and OAuth 2.0 are the Single Sign-On Protocols that are implemented in modern web applications. In this post, we outline common issue patterns that were discovered in popular OpenID Connect implementations, give concrete examples of vulnerabilities, and give recommendations for adjustments to the OpenID Connect specification.
