# DECNET Threat Model

## Purpose

This document is the single source of truth for **what threats DECNET
defends against, what it accepts, and what it considers out of scope.**

Its role is to provide a **stop line** for design discussions: once a
threat is recorded here with a status, it does not need to be
re-litigated in every feature review. New threats get added; existing
ones get re-classified if reality changes; nothing gets deleted without
a note in the change log.

## Methodology — STRIDE per-element

We use STRIDE-per-element (threats-per-element variant), organized by
**trust boundary**. Each major component gets:

1. A **data-flow diagram (DFD)** showing external entities, processes,
   data stores, and the trust boundaries that separate them.
2. A per-flow **STRIDE enumeration** — for each data flow crossing a
   trust boundary, identify threats in each of the six categories:

   | Code | Category | Violates |
   |------|----------|----------|
   | S | Spoofing | Authentication |
   | T | Tampering | Integrity |
   | R | Repudiation | Non-repudiation |
   | I | Information disclosure | Confidentiality |
   | D | Denial of service | Availability |
   | E | Elevation of privilege | Authorization |

3. **Mitigation status** for each threat, chosen from:

   - **Mitigated** — defended in code; link to the mitigation.
   - **Accepted** — the risk is known and deliberately accepted; note
     the reason.
   - **Transferred** — responsibility lies elsewhere (OS, upstream
     library, operator deployment practice).
   - **Needs verification** — plausibly mitigated but the threat model
     author couldn't confirm in code; flag for review.
   - **Out of scope** — explicitly excluded (see the master
     out-of-scope register).

## Risk-acceptance protocol

Accepting a risk is a deliberate act with a written justification. An
"accepted" entry must include:

- **Why** the risk is accepted (cost/benefit, compensating control
  elsewhere, low likelihood × low impact).
- **When** the acceptance should be revisited (e.g. "reassess when
  multi-tenant support lands" or "revisit pre-v1").
- **Who** observed and accepted it (by git commit author on this file —
  no hand-waving).

---

## System context

DECNET is a distributed honeypot platform. The top-level actors and
trust boundaries:

```
                           ┌─────────────────────────┐
                           │ External Attacker       │
                           │ (internet, untrusted)   │
                           └─────────────┬───────────┘
                                         │ TCP/IP (MACVLAN)
                                         ▼
  ── TRUST BOUNDARY: attacker ↔ decoy ──────────────────────────────
                                         │
                           ┌─────────────▼───────────┐
                           │ Decky (honeypot)        │
                           │ service containers      │
                           └─────────────┬───────────┘
                                         │ RFC 5424 syslog
                                         │ (local: UDP; cross-host: TLS 6514)
                                         ▼
  ── TRUST BOUNDARY: decky ↔ master (log ingest) ────────────────────
                                         │
                           ┌─────────────▼───────────┐         ┌──────────────┐
                           │ Master host             │◄────────┤ Swarm agent  │
                           │ ┌──────┐ ┌──────┐       │  mTLS   │ (remote host)│
                           │ │ API  │ │Workers│      │  6514   └──────────────┘
                           │ │ Web  │ │ + Bus │      │
                           │ └──▲───┘ └──┬───┘       │
                           │    │        │            │
                           │ ┌──┴───┐ ┌──▼───┐       │
                           │ │ DB   │ │ Logs │       │
                           │ └──────┘ └──────┘       │
                           └────▲────────────────────┘
                                │ HTTPS + JWT
  ── TRUST BOUNDARY: dashboard user ↔ API ──────────────────────────
                                │
                  ┌─────────────┴───────────┐
                  │ Dashboard user          │
                  │ (viewer / admin role)   │
                  └─────────────────────────┘
```

### Trust boundaries (top-level)

| # | Boundary | Component doc |
|---|----------|---------------|
| 1 | Attacker ↔ Decky (the whole point: attackers cross this by design) | *not yet modeled* |
| 2 | Decky ↔ Master (syslog path) | *not yet modeled* |
| 3 | Swarm agent ↔ Master (mTLS API) | *partially — see* `feedback_mtls_pin_per_host.md` |
| 4 | Dashboard user ↔ API | **[Component 1](#component-1--dashboard-user--api)** ← this doc |
| 5 | Bus client ↔ Bus (local IPC) | *not yet modeled* |
| 6 | Updater daemon ↔ Update source | *not yet modeled* |
| 7 | Federation peer ↔ Federation peer (v2) | *see* `DEVELOPMENT_V2.md` §Federation |

---

## Component 1 — Dashboard user ↔ API

**Status:** first component modeled; sets the template for the rest.
**Scope:** everything the React dashboard sends to `/api/v1/*` and
everything the API sends back. Out of scope for this component:
master↔agent API, service-to-service calls within the master.

### DFD

```
                    ┌────────────────────────────────┐
                    │ Dashboard user (browser)       │
                    │  React SPA, JWT in memory       │
                    └─────────────┬──────────────────┘
                                  │
                                  │ HTTPS (TLS to reverse proxy)
                                  │ JWT in Authorization header
                                  │ (exception: SSE uses ?token=<jwt>)
                                  │
  ══ TRUST BOUNDARY ═══════════════│═══════════════════════════════════
                                  │
                    ┌─────────────▼──────────────────┐
                    │ FastAPI app (decnet api)       │
                    │  ┌─────────────────────────┐   │
                    │  │ Auth middleware / JWT   │   │
                    │  │ decode + role extract   │   │
                    │  └───────────┬─────────────┘   │
                    │              │ authenticated   │
                    │  ┌───────────▼─────────────┐   │
                    │  │ Dependencies:           │   │
                    │  │  require_viewer         │   │
                    │  │  require_admin          │   │
                    │  │  require_master_mode    │   │
                    │  └───────────┬─────────────┘   │
                    │              │ authorized      │
                    │  ┌───────────▼─────────────┐   │
                    │  │ Route handler           │   │
                    │  │  → repo (SQLModel)      │   │
                    │  │  → bus publish          │   │
                    │  │  → artifact filesystem  │   │
                    │  └─────────────────────────┘   │
                    └────────────────────────────────┘
```

### Sub-flows in scope

| ID | Flow | Examples |
|----|------|----------|
| F1 | Authn | `POST /auth/login`, JWT issuance, `POST /auth/change-password` |
| F2 | Authz | every route's `require_*` decoration; role checks at dependency layer |
| F3 | Data reads (non-query) | `GET /attackers/{uuid}`, `GET /deckies/{name}`, `GET /health` |
| F4 | Queries (user-filtered) | `GET /logs?service=&severity=&q=`, `GET /attackers?…`, `GET /bounties?…`, `GET /attackers/{uuid}/commands?service=&limit=&offset=` |
| F5 | Mutations | `PATCH /deckies/*`, `POST /config/*`, `POST /users`, `DELETE /users/{u}`, `POST /topologies`, `POST /topologies/{id}/mutations` |
| F6 | Streaming / SSE | `GET /stream/events?token=`, `GET /topologies/{id}/events?token=` |
| F7 | Downloads | `GET /artifacts/{decky}/{stored_as}?service=` (ssh / smtp), `GET /attackers/{uuid}/mail` |

### STRIDE enumeration

Each sub-flow below gets its own table. Status codes:
**M** = mitigated · **A** = accepted · **T** = transferred ·
**?** = needs verification · **X** = out of scope.

#### F1 — Authn

| Cat | Threat | Status | Notes |
|-----|--------|--------|-------|
| S | Credential stuffing / brute force on `/auth/login` | M | slowapi two-bucket rate limit at `decnet/web/router/auth/api_login.py`: 10/5min per-IP AND 10/5min per-username, tripping either → 429. In-memory storage (`decnet/web/limiter.py`). |
| S | JWT forgery with weak/leaked secret | M | `DECNET_JWT_SECRET` required, 32+ chars; signing verified on every request. Operator deployment responsibility to rotate on suspected leak. |
| S | Stolen JWT replayed from attacker's browser | A | JWT TTL is short; no server-side session revocation pre-v1. Accepted: revisit if customer demands immediate-revocation. |
| T | Password hash tampering in DB | T | DB integrity is OS/filesystem scope. See boundary #2 for syslog-path tampering. |
| R | User denies having performed an action | M | Every mutation logged with actor UUID; audit trail lives in `logs` table. |
| I | Password reflected in login response on failure | M | Single uniform 401 for user-not-found and bad-password at `api_login.py`. No user-existence oracle. |
| I | JWT secret leaked via error message / stack trace | M | Generic `@app.exception_handler(Exception)` at `decnet/web/api.py` returns opaque `{detail, error_id}` on uncaught exceptions; traceback is logged server-side only. Dev-mode (`DECNET_DEVELOPER=True`) includes traceback in body for debugging. |
| D | Bcrypt-cost DoS via long password submission | M | Pydantic `max_length=72` on all password fields in `decnet/web/db/models/auth.py` (matches bcrypt's internal truncation limit). |
| E | `role=None` bypass (historical bug) | M | See memory `project_rbac_null_role.md`; fixed via centralized RBAC that treats `None` as unauthenticated. |

#### F2 — Authz

| Cat | Threat | Status | Notes |
|-----|--------|--------|-------|
| S | Forged role claim in JWT | M | Role read from DB by UUID on each authz, not trusted from token. (Verify — see `project_rbac_null_role.md`.) |
| T | Client-side role flag tampering | M | Server-side gating required; client-side hide-only is UI polish. See `feedback_serverside_ui.md`. |
| R | Admin denies granting a role | M | `update_user_role` calls logged. |
| I | Route missing `require_*` accidentally exposes admin data to viewer | **?** | Verify: schemathesis / contract tests assert 401/403 on every protected route. Recommend a test that enumerates all routes and asserts gating. |
| D | n/a (authz is a check, not a bottleneck) | — | |
| E | Viewer crafts path traversal in URL to hit admin route | M | FastAPI path matching is exact; no dynamic include. |
| E | Master-only CLI command reachable in agent mode | M | `MASTER_ONLY_COMMANDS` gating at CLI registration + `_require_master_mode()` guard in handler. |

#### F3 — Data reads (non-query)

| Cat | Threat | Status | Notes |
|-----|--------|--------|-------|
| S | (same as F2) | — | |
| T | Response body tampered in transit | T | TLS to reverse proxy is operator-deployment scope. |
| R | n/a (read-only) | — | |
| I | Non-existent resource returns different status than forbidden | M | Attacker-not-found returns 404 after authz passes, consistent with other handlers. |
| I | Sensitive fields bleed into viewer response (e.g. attacker PII) | **?** | Verify: field allow-listing on attacker serializer for viewer role. |
| D | Heavy single-resource fetch (rare) | A | Unbounded fetch on a single row is bounded by row size. Accepted. |
| E | n/a (no privilege change) | — | |

#### F4 — Queries (densest threat surface)

| Cat | Threat | Status | Notes |
|-----|--------|--------|-------|
| S | (inherited from authn/authz) | — | |
| T | SQL injection via filter params | M | SQLModel uses parameterized queries exclusively; no string-concatenation SQL in repo. Verify on each new query endpoint. |
| T | ORM expression injection (e.g. sort-by-arbitrary-column) | **?** | Verify: sort/filter keys are allow-listed, not passed through raw. |
| R | Query log does not record who queried what | A | Pre-v1: query audit log out of scope. Revisit if customer demands query-level audit. |
| I | Filter-bypass exfiltration: viewer filters return admin-visible rows | **?** | Verify: repo methods take the caller's role and scope results, OR routes pre-filter, OR data is viewer-safe by schema. Currently assumed "viewer-safe by schema" — worth asserting in a test. |
| I | Timing side channel reveals existence of filtered-out rows | A | Micro-timing attacks on SQLite not a realistic threat for this workload. Accepted. |
| I | Error message (422 / 500) leaks column names or SQL fragments | M | FastAPI 422 is schema-shaped; 500 handler must not return tracebacks in prod. Verify handler config. |
| I | Schema enumeration via schemathesis-style fuzzing | A | Schemathesis contract tests document 400/422 shape; an attacker learning the schema gains nothing beyond the public OpenAPI spec. See `feedback_schemathesis_400.md`. |
| D | Unbounded result set via missing `limit` | **?** | Verify: every query endpoint has a hard server-side cap independent of the `limit` param. |
| D | Deep-pagination scan via large `offset` | **?** | Verify: `offset` is capped, OR pagination is cursor-based, OR the table has an index that makes deep offsets cheap. |
| D | Expensive `LIKE '%foo%'` on non-indexed column | **?** | Verify: free-text `q` params hit an FTS5 virtual table or indexed column, not `LIKE`-scan of a large table. |
| D | Repeated expensive queries from single user | A | Per-user rate limiting is out of scope pre-v1. Operator-deployment mitigation: reverse-proxy rate limit. |
| E | Filter params allow reading across tenants (future multi-tenant) | X | Multi-tenant is not in the v1 model; revisit when tenants exist. |

#### F5 — Mutations

| Cat | Threat | Status | Notes |
|-----|--------|--------|-------|
| S | Forged mutation from non-authenticated client | M | `require_admin` on all mutations; JWT enforced. |
| T | Replay of a captured mutation request | A | No nonce/idempotency-key pre-v1. Accepted: admin role already has full mutation power; replay gains nothing a fresh request couldn't. Revisit if multi-admin audit becomes a requirement. |
| T | Concurrent-write race corrupting state | **?** | Verify: SQLModel session scoping + DB-level constraints cover the likely races (user creation, topology CRUD). |
| R | Admin denies having mutated | M | Actor UUID + timestamp logged on every mutation. |
| I | Mutation response returns internal state not meant for client | **?** | Verify per-route response_model shape. |
| D | Malformed body triggers expensive validation / oversized payload | M | FastAPI enforces content-length at ASGI layer; Pydantic short-circuits on type mismatch. |
| D | Destructive mutation storm (e.g. delete-all-users) | A | Admin role is trusted; protecting admins from themselves is out of scope. |
| E | Mutation bypasses role check via missing `require_admin` | **?** | Verify via schemathesis: every mutation route returns 403 for viewer. |

#### F6 — Streaming / SSE

| Cat | Threat | Status | Notes |
|-----|--------|--------|-------|
| S | Token-in-query-string logged by reverse proxy / browser history | A | SSE cannot use Authorization header; `?token=<jwt>` is the standard workaround. Mitigation: short JWT TTL, operator must scrub access logs if compliance requires. Document explicitly. |
| T | Injected events into the stream from another client | M | Events are repo→bus→SSE one-way; no client-to-client. |
| R | User denies having observed events | X | Passive read; non-repudiation n/a. |
| I | SSE forwards events the user's role shouldn't see | **?** | Verify: per-connection role filter in the SSE handler. |
| D | Connection exhaustion (hold many SSE connections open) | **?** | Verify: per-user concurrent-connection cap. |
| E | n/a | — | |

#### F7 — Downloads

| Cat | Threat | Status | Notes |
|-----|--------|--------|-------|
| S | (inherited) | — | |
| T | Path-traversal via `{decky}` or `{stored_as}` to read arbitrary files | M | Pattern-validated at FastAPI layer (`{service}` is `^[a-z]{1,16}$`; artifact names are UUID-shaped). Verify: resolved path is contained under the artifacts root. |
| R | Admin denies having downloaded | M | Download endpoint emits an access log entry. |
| I | Viewer accesses attacker-controlled bytes | M | Admin-gated (`require_admin`). Rationale: artifacts are phishing kits / malware droppers / attacker-controlled content — see `api_get_attacker_mail.py` docstring. |
| I | MIME sniffing / content-type confusion executes attacker payload in browser | **?** | Verify: response sets `Content-Disposition: attachment` and `X-Content-Type-Options: nosniff`. |
| D | Gigabyte-sized artifact download ties up workers | M | SMTP body cap is 10 MB (EHLO SIZE enforcement); SSH artifact sizes bounded by disk quota. |
| E | Downloaded artifact escapes the browser sandbox | T | Browser security boundary is transferred to the browser vendor and operator's endpoint protection. |

### Accepted risks (Dashboard ↔ API)

Consolidated for easy reference:

| ID | Threat | Why accepted | Revisit when |
|----|--------|--------------|--------------|
| DA-01 | Stolen JWT replayable until TTL expiry | Server-side revocation list is infra cost disproportionate to v1 threat model | Customer demands immediate revocation, OR swarm-scale deployment where JWT theft blast radius grows |
| DA-02 | Query-level audit log absent | Admin-mutation audit is sufficient pre-v1 | Regulated-industry customer engagement |
| DA-03 | Query-filter timing side channel | SQLite + single-tenant; impact is negligible | Multi-tenant support lands |
| DA-04 | Per-user query rate limiting absent | Trusted operator deployment; reverse-proxy rate limit is the operator's responsibility | SaaS / multi-tenant hosting model |
| DA-05 | Mutation replay within admin session | Replay grants no privilege a fresh request wouldn't | Multi-admin audit requirement |
| DA-06 | Destructive admin mutations not protected against the admin | Trusted-admin assumption; protecting root from root is out of scope | Multi-admin RBAC with mutual-approval workflows |
| DA-07 | SSE token in query string | No alternative in the SSE spec; operator must control access-log handling | Move to WebSocket with in-band auth |
| DA-08 | Reverse-proxy deployments collapse per-IP rate-limit bucket to one shared bucket | `X-Forwarded-For` is spoofable by any client; trusting it defeats the rate limit. Operators behind a proxy get coarser granularity but no spoofing lane. | Verified-proxy config lands (allow-list of proxy IPs whose `X-Forwarded-For` we trust) |

### Needs-verification checklist (Dashboard ↔ API)

Drop-in TODO list — each entry resolves to either "mitigated, link to
code" or "accepted, add to table above."

- [x] ~~Per-IP / per-user rate limit on `/auth/login`.~~ Shipped — see F1/S row.
- [x] ~~Uniform "invalid credentials" on login failure (no user-existence oracle).~~ Verified — see F1/I row.
- [x] ~~Production error handler suppresses tracebacks and internal details.~~ Shipped — generic `@app.exception_handler(Exception)` in `decnet/web/api.py`; opaque `{detail, error_id}` in prod, traceback only under `DECNET_DEVELOPER=True`.
- [ ] `detail=str(e)` / `detail=f"…{e}"` sites in `decnet/web/router/fleet/api_deploy_deckies.py:41,67,83,155` — admin-gated, arguably intentional INI-parser UX, but worth auditing: preserve deliberate messages, sanitize any bubble-up from lower layers.
- [x] ~~Password length clamp before bcrypt.~~ Verified — Pydantic `max_length=72`.
- [ ] Contract test asserting every protected route returns 401 unauthenticated and 403 for under-roled.
- [ ] Field allow-list on viewer responses for attacker / user / bounty serializers.
- [ ] Sort/filter query keys are allow-listed, not passed through raw.
- [ ] Role-scoped repo methods OR per-route pre-filter for viewer queries (pick one, document it).
- [ ] Every query endpoint has a server-side hard cap independent of `limit`.
- [ ] `offset` is capped OR pagination is cursor-based OR deep-offset is cheap.
- [ ] Free-text `q` parameters hit an indexed/FTS5 column, never a full-table `LIKE` scan.
- [ ] Per-route response_model shape audit on mutations.
- [ ] Contract test asserting every mutation route returns 403 for viewer.
- [ ] SSE handler applies per-connection role filter before forwarding events.
- [ ] Per-user concurrent SSE connection cap.
- [ ] Artifact download sets `Content-Disposition: attachment` + `X-Content-Type-Options: nosniff`.
- [ ] Artifact path resolution asserts the resolved path is under the artifacts root (canonicalize + prefix check).

### Out of scope (this component)

- TLS termination correctness (operator's reverse proxy).
- Browser-side XSS originating from user-controlled content rendered in the dashboard (that's a frontend threat model, separate document when we write one).
- Physical access to the master host.
- Supply-chain compromise of FastAPI / SQLModel / dependencies (upstream / OS scope).
- Denial of service at the network layer (operator deployment).

---

## Master out-of-scope register

These threats are excluded from the DECNET threat model entirely,
regardless of component:

- **Physical attacker at the master or agent console.** Disk
  encryption, console access, BMC/iLO security is the operator's
  responsibility.
- **Nation-state zero-days in Linux kernel / systemd / Docker.**
- **Upstream supply-chain compromise of Python packages or base images**
  beyond what `pip-audit` + the pre-commit hook catches.
- **Side channels at the hardware level** (Spectre, Rowhammer, etc.).
- **Attacks on the operator's own endpoint** (laptop used to access the
  dashboard).

## Master accepted-risks register

*(Consolidates per-component accepted entries as they are added.)*

| Component | ID | Summary |
|-----------|----|---------|
| Dashboard↔API | DA-01..DA-07 | See component section. |

## Components not yet modeled

In priority order:

1. Decky ↔ Master (syslog path) — data-integrity critical.
2. Swarm agent ↔ Master (mTLS) — existing pinning; document it.
3. Federation peer ↔ Peer — see `DEVELOPMENT_V2.md` §Federation for
   analysis; migrate into this doc when v2 lands.
4. Bus client ↔ Bus — local IPC, narrow surface.
5. Updater daemon ↔ Update source.
6. Decky itself (attacker-facing surface) — largest S/T/E surface; do
   this once the internal boundaries are modeled.

## Change log

| Date | Change | Author |
|------|--------|--------|
| 2026-04-23 | Initial scaffold. System context + Dashboard↔API as first worked component. | ANTI |
| 2026-04-23 | F1 Authn: 3 threats moved from **?** to **M** (rate limit shipped; uniform 401 verified; bcrypt length clamp verified). Added DA-08 accepted risk: reverse-proxy per-IP bucket collapse. | ANTI |
| 2026-04-23 | F1/I "traceback / stack trace leakage" moved from **?** to **M** via generic Exception handler with `error_id` correlation. Added follow-up checklist entry for `detail=str(e)` sites in fleet deploy router. | ANTI |