stride-threat-model

name	stride-threat-model
description	Use when the operator asks for a STRIDE threat model, security review of an architecture, or asks "what could go wrong" about a system design. Wraps the structured STRIDE methodology and produces an actionable threat register.

STRIDE threat model

STRIDE = Spoofing, Tampering, Repudiation, Information Disclosure, DoS, Elevation of Privilege.

Inputs you need

1. System diagram — components + data flows + trust boundaries. ASCII/mermaid is fine.
2. Asset inventory — what's worth attacking (data, accounts, infra).
3. Trust model — who is trusted at each boundary.
4. Existing controls — auth, encryption, monitoring, segmentation.

If any input is missing, ask one sharp question. Don't guess.

Method

1. Decompose the system into components and data flows. Mark trust boundaries explicitly.
2. For each component AND each flow, walk all six STRIDE categories. Generate threats.
3. For each threat: rate likelihood (low/med/high) × impact (low/med/high) → priority.
4. Map controls (existing + recommended). Identify gaps.
5. Output a threat register + Cortex/PANW-style summary.

Output template

# Threat Model — <system>
**Date:** <YYYY-MM-DD>  **Reviewer:** Henry  **Spec version:** <ref>

## Executive summary
<one paragraph, business language, names top 3 risks + recommended action>

## Architecture (decomposed)
```mermaid
<component diagram with trust boundaries>

Threat register

ID	Component	Category	Threat	Likelihood	Impact	Priority	Existing control	Recommended control
T-001	API gateway	Spoofing	...	M	H	P1	mTLS to backend	Add JWT iss/aud validation

Recommended detections (Cortex XSIAM/XDR)

• T-001: XQL rule sketch: dataset = http_logs | filter ...
• ...

Open questions

• ...

## Defaults

- Default to **high-impact, plausibly-likely** threats. Don't pad with theoretical exotics unless the ask is explicitly comprehensive.
- For Cortex/PANW pre-sales: every threat that maps to an XSIAM/XDR detection should include the rule sketch.
- Use mermaid for the architecture diagram. Keep it under 15 nodes.