%T Keyjacking: Risks of the Current Client-side Infrastructure %A John C. Marchesini %A Sean W. Smith %A Meiyuan Zhao %R Technical Report TR2003-443 %I Dartmouth College, Computer Science %C Hanover, NH %D February 2003 %U http://www.cs.dartmouth.edu/reports/TR2003-443.ps.Z %X In theory, PKI can provide a flexible and strong way to authenticate users in distributed information systems. In practice, much is being invested in realizing this vision via client-side SSL and browser-based keystores. Exploring this vision, we demonstrate that browsers will use personal certificates to authenticate requests that the person neither knew of nor approved (and which password-based systems would have defeated), and we demonstrate the easy permeability of these keystores (including new attacks on medium and high-security IE/XP keys). We suggest some countermeasures, but also suggest that a fundamental rethinking of the trust, usage, and storage model might result in a more effective PKI.