The standardized OASIS Security Assertion Markup Language (SAML) has become one of the most deployed frameworks in federated identity management even though it focuses only on single sign-on. Answering industry's pursuit of the reduction of user-management costs and enabling cost-efficient deployment because of its browser-based profiles, SAML is believed to become widely used soon. With the revision to Version 2.0, especially SAML's browser/artifact profile has gained new security measures defeating old vulnerabilities. We analyze this profile and focus on the problem of artifact information flow. We devise a concrete exploit to demonstrate the impact of this problem. We address this problem by a new browser/artifact profile called Janus. The innovation is to split the artifact into two independent shares that have different information flow in a standard web browser. This new method defeats artifact information flow efficiently without relying on assumptions on the artifact lifetime.
By: Thomas Gross and Birgit Pfitzmann
Published in: RZ3643 in 2006
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