Security Threat Model Skill

Produce a complete STRIDE-based threat model for a service or feature. A threat model is not a list of things that could go wrong — it is a structured analysis of attackers, assets, boundaries, and controls that lets an engineering team make informed, documented security decisions.

A good threat model is specific enough that a new engineer can understand what is being protected, why each control exists, and what risk the team has accepted.

Required Inputs

Ask for these if not already provided:

• Service name and description — what the service does, who uses it
• Architecture overview — components, dependencies, data flows (a diagram description or ASCII diagram is fine)
• Deployment environment — cloud provider, VPC/network topology, where it runs (Kubernetes, ECS, VMs, serverless)
• Data sensitivity — what data does this service handle? PII, payment data, credentials, internal-only?
• Existing controls — authentication method, encryption in transit/at rest, current WAF/firewall, existing security scanning
• Trust levels — who are the principals? (anonymous public, authenticated users, internal services, admins)

Output Format