OpenID Connect

Abstract: The OAuth 2.0 protocol is one of the most widely deployed authorization/single sign-on (SSO) protocols and also serves as the foundation for the new SSO standard OpenID Connect. Despite the popularity of OAuth, so far analysis efforts were mostly targeted at finding bugs in specific implementations and were based on formal models which abstract from many web features or did not provide a formal treatment at all. In this paper, we carry out the first extensive formal analysis of the OAuth 2.0 standard in an expressive web model. Our analysis aims at establishing strong authorization, authentication, and session integrity guarantees, for which we provide formal definitions. In our formal analysis, all four OAuth grant types (authorization code grant, implicit grant, resource owner password credentials grant, and the client credentials grant) are covered. They may even run simultaneously in the same and different relying parties and identity providers, where malicious relying parties, identity providers, and browsers are considered as well. Our modeling and analysis of the OAuth 2.0 standard assumes that security recommendations and best practices are followed in order to avoid obvious and known attacks. When proving the security of OAuth in our model, we discovered four attacks which break the security of OAuth. The vulnerabilities can be exploited in practice and are present also in OpenID Connect. We propose fixes for the identified vulnerabilities, and then, for the first time, actually prove the security of OAuth in an expressive web model. In particular, we show that the fixed version of OAuth (with security recommendations and best practices in place) provides the authorization, authentication, and session integrity properties we specify.

Abstract: This document gives additional security considerations for OAuth, beyond those in the OAuth 2.0 specification, based on a comprehensive threat model for the OAuth 2.0 protocol. This document is not an Internet Standards Track specification; it is published for informational purposes.

Abstract: Globus Auth is a foundational identity and access management platform service designed to address unique needs of the science and engineering community. It serves to broker authentication and authorization interactions between end-users, identity providers, resource servers (services), and clients (including web, mobile, desktop, and command line applications, and other services). Globus Auth thus makes it easy, for example, for a researcher to authenticate with one credential, connect to a specific remote storage resource with another identity, and share data with colleagues based on another identity. By eliminating friction associated with the frequent need for multiple accounts, identities, credentials, and groups when using distributed cyberinfrastructure, Globus Auth streamlines the creation, integration, and use of advanced research applications and services. Globus Auth builds upon the OAuth 2 and OpenID Connect specifications to enable standards-compliant integration using existing client libraries. It supports identity federation models that enable diverse identities to be linked together, while also providing delegated access tokens via which client services can obtain short term delegated tokens to access other services. We describe the design and implementation of Globus Auth, and report on experiences integrating it with a range of research resources and services, including the JetStream cloud, XSEDE, NCAR's Research Data Archive, and FaceBase.

Abstract: Correctly integrating third-party services into web applications is challenging, and mistakes can have grave consequences when third-party services are used for security-critical tasks such as authentication and authorization. Developers often misunderstand integration requirements and make critical mistakes when integrating services such as single sign-on APIs. Since traditional programming techniques are hard to apply to programs running inside black-box web servers, we propose to detect vulnerabilities by probing behaviors of the system. This paper describes the design and implementation of SSOScan, an automatic vulnerability checker for applications using Facebook Single Sign-On (SSO) APIs. We used SSOScan to study the twenty thousand top-ranked websites for five SSO vulnerabilities. Of the 1660 sites in our study that employ Facebook SSO, over 20% were found to suffer from at least one serious vulnerability.