Who Are You? A Statistical Approach to Measuring User Authenticity

Passwords are used for user authentication by almost every Internet service today, despite a number of wellknown weaknesses. Numerous attempts to replace passwords have failed, in part because changing users' behavior has proven to be difficult. One approach to strengthening password-based authentication without changing user experience is to classify login attempts into normal and suspicious activity based on a number of parameters such as source IP, geo-location, browser configuration, and time of day. For the suspicious attempts, the service can then require additional verification, e.g., by an additional phone-based authentication step. Systems working along these principles have been deployed by a number of Internet services but have never been studied publicly. In this work, we perform the first public evaluation of a classification system for user authentication. In particular: