Publication Date

Fall 2012

Degree Type

Master's Project

Degree Name

Master of Science (MS)


Computer Science


In this paper, we consider the problem of masquerade detection based on a UNIX system. A masquerader is an intruder who tries to remain undetected by impersonating a legitimate user. Masquerade detection is a special case of the general intrusion detection problem. We have collected data from a large number of users. This data includes infor- mation on user commands and a variety of other aspects of user behavior that can be used to construct a profile of a given user. Hidden Markov models have been used to train user profiles, and the various attack strategies have been analyzed. The results are compared to a standard dataset that offers a more limited view of user behavior.