So no evidence lolSecurity Evaluation of ES&S Voting Machines and Election Management System (usenix.org) July 2007
Despite our admittedly incomplete analysis, we identified numerous critical vulnerabilities in nearly every component of the ES&S system. We describe serious practical and undetectable attacks that could be carried out by pollworkers, and in many cases, individual voters. (As a noteworthy example, a voter can surreptitiously delete all vote data and audit logs stored on a touchscreen voting machine using a Palm handheld device and a small magnet.) Such attacks could alter or forge precinct results, install corrupt firmware, and erase audit records. Of particular concern, several attacks could spread virally, propagating between voting machines and backend systems, and vice versa.