Documentation: Capturing and Communicating Threats

Effective threat modeling requires clear, comprehensive documentation that captures findings and communicates them to various stakeholders. Documentation serves multiple purposes: it provides a historical record, enables consistent analysis, facilitates communication, and supports decision-making. Understanding what to document and how to present it ensures threat modeling efforts produce actionable results.

Visual documentation through diagrams and models makes complex systems understandable. Data flow diagrams show how information moves through systems, highlighting trust boundaries and potential interception points. Attack trees illustrate how multiple vulnerabilities might chain together to achieve attacker objectives. Architecture diagrams reveal system components and their interactions. These visual elements make threat discussions concrete and accessible to non-technical stakeholders.

Textual documentation complements visual elements with detailed threat descriptions, risk assessments, and recommended controls. Threat catalogs list identified threats with their properties, enabling tracking and management. Risk registers document assessment results and mitigation decisions. Control matrices map threats to implemented or recommended countermeasures. This structured documentation enables systematic threat management and progress tracking.

Living documentation acknowledges that threat models must evolve with systems and threat landscapes. Version control, regular reviews, and update procedures ensure documentation remains relevant. Integration with development processes and security tools maintains documentation currency without creating excessive overhead. The goal is documentation that actively supports security efforts rather than gathering dust on virtual shelves.

Understanding these core components provides the foundation for effective threat modeling. Assets define what needs protection, threat actors indicate who might attack, attack vectors show how attacks occur, vulnerabilities reveal what enables attacks, trust boundaries indicate where controls apply, security controls provide defense, risk assessment prioritizes efforts, and documentation captures and communicates findings. Together, these components create comprehensive threat models that transform security from reactive to proactive. The following chapters will build on this foundation, introducing specific methodologies and techniques for applying these components in your threat modeling practice.## Getting Started: Your First Threat Model

Taking the first step in threat modeling can feel overwhelming, especially when faced with complex methodologies and extensive security frameworks. However, every expert threat modeler started with their first model, learning and refining their approach through practice. This chapter provides a practical, step-by-step guide to creating your first threat model, demystifying the process and building confidence through hands-on experience. By the end of this chapter, you'll have completed a basic threat model and understand how to apply these techniques to your own systems.