er abstract summarizes the Threat Modeling method based on Attacking Path Analysis (T-MAP) which quantifies and prioritizes security threats by calculating the total severity weights of relevant attacking paths for Commercial Off The Shelf (COTS) based systems. Compared to existing approaches, T-MAP is dynamic and sensitive to system stakeholder value priorities and IT environment. It distills the technical details of thousands of relevant software vulnerabilities into management-friendly numbers at a high-level. In its initial usage in a large IT organization, T-MAP has demonstrated significant strength in COTS vulnerability prioritizing and estimating security investment effectiveness, as well as COTS security assessment in early project life-cycle. Furthermore, a software tool has been developed to automate the T-MAP.