Abstract : Malicious software and hostile intrusions represent two of the largest threats to information systems today. During the course of this project we developed solutions that address both of these issues. The BayeScan prototype is a novel approach to detecting malicious software before it has a chance to strike. The AppID prototype provides a framework for the development of real-time host-based intrusion detection technology. The creation of these tools provides users with access to leading-edge research technologies in the fight against malicious software and malicious attackers.