threat-model-lite

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name: threat-model-lite description: Lightweight, repeatable threat modeling for a feature or service with prioritized mitigations.

Use this skill when planning a feature, reviewing an architecture, or preparing security requirements.

Step-by-step process

1. Define scope
   • What is being built/changed? What is explicitly out of scope?
2. Describe the system
   • Components, identities, data stores, external dependencies
3. Identify assets
   • Secrets, PII, money-moving actions, admin capabilities, integrity-critical data
4. Map trust boundaries
   • Internet ↔ edge, edge ↔ app, app ↔ data, service ↔ service
5. List top threats (ranked)
   • Use STRIDE reasoning; focus on realistic threats
6. Mitigations
   • Prevent: validation, authz, rate limiting, encryption
   • Detect: logs, alerts, anomaly detection
   • Respond: rollback, key rotation, incident playbooks
7. Residual risk
   • What remains and why; follow-ups

Output template

• System overview
• Data flows (bulleted)
• Assets
• Trust boundaries
• Top threats + mitigations
• Residual risk + next steps