Getting Started with Threat Modeling

Beginning your threat modeling journey doesn't require perfection or comprehensive expertise. Start by selecting a single system or application—preferably one that's well-understood but security-critical. Gather a small team including someone who understands the system architecture, someone familiar with how it's used, and ideally someone with security knowledge. This diversity of perspectives enhances threat identification.

Create a simple diagram showing how data flows through your system. Identify what needs protection (assets), who might want to attack (threat actors), and how they might do so (attack vectors). Don't worry about using formal methodologies initially; focus on thinking like an attacker. What would you target? How would you try to break in? What damage could you cause? These questions start revealing vulnerabilities.

Document your findings and prioritize them based on likelihood and impact. High-likelihood, high-impact threats demand immediate attention. Lower-priority threats can be addressed over time. The key is starting the process and improving iteratively. As your team gains experience, you can adopt formal methodologies and tools that provide structure and consistency to your threat modeling efforts.