This paper describes an asset vulnerability model decision support tool (AVM-DST) that is designed to guide strategic investments in critical infrastructure protection. AVM-DST is predicated on previous research on an alternative risk methodology for assessing the current infrastructure protection status, evaluating future protective improvement measures and justifying national investments. AVM-DST is a web-based application that works within the U.S. Department of Homeland Security Risk Management Framework and enables decision makers to view infrastructure assets risk profiles that highlight various features of interest, select protective improvement measures within a given budget based on defined investment strategies or other criteria, and evaluate protective purchases against varying probabilities of attack over a given period of time. In addition to reviewing the concepts and formulations underlying the application, this paper describes the AVM-DST capabilities, functions, features, architecture and performance.