How (Not) to Use OAuth in 2024 (god2024)

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OAuth 2.0 has become the backbone of secure delegated authorization on the web, enabling users to grant third-party applications access to their data without revealing their credentials. It's also foundational for federated authentication via OpenID Connect and plays a critical role in emerging technologies like wallet ecosystems. However, despite its wide adoption, OAuth implementations are fraught with risks — many of which can lead to serious security breaches. The challenges arise from OAuth's use in contexts far more dynamic and high-stakes than what was originally envisioned. Today, OAuth protects sensitive financial APIs, powers identity verification systems, and secures modern app ecosystems — yet, many implementations remain vulnerable to attack. Even with the guidance from RFC6749 and RFC6819, subtle misconfigurations and outdated practices are still common, often due to the complexities of real-world deployments. To address these evolving security needs, the IETF is finalizing the OAuth 2.0 Security Best Current Practice (BCP), an updated set of recommendations designed to mitigate common vulnerabilities and improve OAuth implementations across industries. This new RFC introduces stronger security measures and deprecates insecure approaches like the Implicit Grant, while also tackling new threats such as the Authorization Server Mix-Up Attack. In this talk, we will dive into the core challenges of securing OAuth in today's dynamic and high-stakes environments. Attendees will learn about the most critical updates from the Security BCP, including the MUSTs, MUST NOTs, and SHOULDs that are essential for robust OAuth implementations. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://c3voc.de