Threat Modeling Best Practices

What this best practices guide is

A practical guide to threat modeling for development teams who want it to be a normal part of design, not a yearly workshop. It covers the four questions, data flow diagrams and trust boundaries, STRIDE and abuse cases, rating and responding to threats, turning them into tickets and tests, keeping models current, and threat modeling features built on language models and agents.

It has 6 chapters and 24 practices, each with why it matters, what to do and what to avoid. For developers and tech leads who design features.

Chapter by chapter

1. The four questions and the right mindset (4 practices)

What threat modeling is for, when to do it, and who should be in the room. The four questions give every session the same simple shape.

2. What are we working on: diagrams and trust boundaries (4 practices)

A shared picture of the system is the foundation. This chapter covers data flow diagrams, trust boundaries, scope, and keeping the model where the team can update it.

3. What can go wrong: STRIDE, abuse cases and attack trees (4 practices)

Structured prompts find more threats than open brainstorming. This chapter covers STRIDE per element, abuse cases, attack trees and privacy threats.

4. What are we going to do about it: decisions, tickets and tests (4 practices)

A threat model is only worth the changes it causes. This chapter covers choosing a response, ranking threats, and turning decisions into work the team tracks and tests.

5. Making threat modeling routine and keeping models current (4 practices)

Threat modeling pays off when it is a normal step for every significant change. This chapter covers a lightweight per-feature practice, checking the work, and keeping models alive.

6. Threat modeling LLM and agent features (4 practices)

Features built on language models add new trust boundaries: text that can act like instructions, outputs that reach other systems, and tools the model can call. The OWASP Top 10 for LLM Applications (2026 edition) gives the prompts.

How it works on Sefism

The guide reads like a short course: a syllabus, then one chapter per page in a focused reader, with a quiz at the end of each chapter for members. The opening chapters are open to everyone. Adding it to your account uses credits, opens every chapter and keeps your progress.

Every claim is checked against the sources listed on the page (6 cited).