threat-model-discipline

Threat-Model Discipline

Overview

You cannot test what you have not modeled. A threat model names the assets, entry points, trust boundaries, relevant ATT&CK techniques, and existing mitigations — so coverage is deliberate, not accidental. On a long engagement the surface drifts (a new endpoint, a new dependency); un-reviewed drift is where bugs hide. This skill keeps the model complete and re-checks it for drift.

When to Activate

• At engagement start (after recon-osint), before weaponize/exploit.
• Whenever recon is re-run or the target changes — to catch new attack surface.
• At /engage.gate — the gate refuses to advance on un-acknowledged drift.

The model (JSON, materialized from recon)

threat-model.json (see templates/threat-model/): five required lists — assets, entry_points, trust_boundaries, attck (technique ids), mitigations.

# 1. Lint - every required field present, no placeholders, valid ATT&CK ids
python skills/threat-model-discipline/scripts/threatmodel_lint.py lint .engage/recon/threat-model.json

# 2. Drift - diff a re-run against the reviewed baseline; NEW entry points/assets/boundaries are
#    unreviewed surface and BLOCK the gate until re-reviewed or acknowledged
python skills/threat-model-discipline/scripts/threatmodel_lint.py drift \
    .engage/recon/threat-model.baseline.json .engage/recon/threat-model.json

Or use /engage.threatmodel (materialize | lint | drift).

Red Flags — STOP

• "We'll model it as we go" — unmodeled surface = untested surface. Model first.
• "Recon changed but the threat model didn't" — re-run drift; new surface must be re-reviewed.
• A threat model full of TBD/[fill in] — that is not a model; the lint fails it.
• A new entry_point appeared and you proceeded anyway — that is the exact gap attackers use.

Rationalizations

Excuse	Reality
"The model is obvious, skip it"	Obvious to you ≠ documented. Coverage you can't diff is coverage you can't trust.
"Drift is just noise"	A new entry point is new attack surface. Acknowledge it explicitly or re-review.
"ATT&CK mapping is busywork"	It turns 'we tested stuff' into 'we covered these techniques' — the report's backbone.

Pairs with scope-discipline (what you may touch) and finding-discipline (what counts as proven).