cypherctrl

Project · Active · started

Threat Modelling AI Systems: From LLM Features to Agents

A practical method for threat modelling anything built on a language model, from a single chat feature to agents that plan, call tools and keep memory. It combines STRIDE, CSA's MAESTRO layers and the OWASP Top 10 for Agentic Applications into one worksheet a product team can actually run.

The kitsune on its cipher disk, reading CYPHER and CTRL The kitsune on its cipher disk, reading CYPHER and CTRL

Scope

Most teams shipping AI features either skip threat modelling or reuse a web-app template that misses the parts that matter: untrusted content steering the model, tools acting with the user’s authority, memory that outlives the session. This project builds a method that scales with autonomy: a lightweight pass for an LLM feature, and a deeper one once the system plans, calls tools or talks to other agents.

The method maps three existing bodies of work onto each other instead of inventing a new framework:

  • STRIDE for the questions engineers already know how to ask.
  • CSA MAESTRO’s seven layers to make sure nothing between the model and the ecosystem around it is left out.
  • The OWASP Top 10 for Agentic Applications (ASI01–ASI10) as the checklist of risks that have already happened in the wild.

Status

Scoping. The first write-up covers a single LLM feature end to end; the agentic extension follows.

Planned artifacts

  • Threat-model worksheet (STRIDE × MAESTRO layer × OWASP ASI risk)
  • Worked example: a retrieval-augmented support assistant
  • Worked example: a coding agent with repository and CI access

References