The OMG® Systems Assurance (SysA) Task Force is working on Model-based Cybersecurity Assessment (MBCA). MBCA is a risk assessment paradigm that emphasizes the use of rigorous models, analytics, and automated tools and best practices for the repeatable assessments of the cybersecurity of systems. MBCA is aligned with Model-Based Systems Engineering (MBSE) and emphasizes leveraging engineering models for the purposes of risk assessment. This presentation will discuss how to use MBCA with the Unified Architecture Framework (UAF) to identify, analyze, classify and understand cybersecurity threats and related risks. This assessment will help stakeholders determine where to focus mitigation efforts, budget and resources.