Threat Modeling for Safer Applications
Threat modeling is a practical approach to build safer apps. It helps teams think like attackers and spot problems before they become bugs. Used early, it keeps security affordable and manageable.
Start by listing assets you must protect: user data, credentials, payment details, API keys, and internal services. Then identify who interacts with the system—users, admins, partners—and where trust changes hands. A simple data flow helps: a user login request moves from the browser to a frontend service, then to an API, and finally to the database. This map shows where an attacker could interfere.
Use a basic threat framework like STRIDE to brainstorm threats in each area: Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege. For each threat, ask how likely it is, what the impact would be, and what would mitigate it. This keeps thinking grounded and concrete.
Risk and mitigations go hand in hand. Rate likelihood as low, medium, or high, and rate impact similarly. Focus on the high risks and link each one to a concrete action: add MFA, improve password storage, enforce input validation, apply rate limits, or segment sensitive data. Document decisions so future teams can follow the rationale.
Example: a login API. Threats include credential stuffing, session hijacking, weak password storage, insecure tokens, and missing MFA. Mitigations: rate limiting, multi-factor authentication, strong password hashing (Argon2, bcrypt), secure cookies, short-lived tokens, and token revocation. This turns scary ideas into practical protections.
To keep threat modeling useful, keep it lightweight. Involve designers, developers, and operators, and set a time box of a few hours for a small project. Document decisions, owners, and follow up in testing and design reviews. Threat modeling is not a one-off task—it evolves with the product and the team.
Key Takeaways
- Start with assets, data flows, and threats to guide security work.
- Apply simple methods like STRIDE and risk ranking to prioritize fixes.
- Integrate threat modeling into design reviews and testing for ongoing safety.