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feat(api): rate-limit /auth/login + scaffold threat model

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Adds slowapi two-bucket rate limit on /auth/login — 10 attempts per
5 minutes per-IP AND per-username, tripping either → 429. Per-IP
catches botnets hitting one account; per-username catches distributed
credential stuffing against one account. In-memory storage: dashboard
API is single-process, Redis is disproportionate for v1.

X-Forwarded-For is deliberately NOT trusted (spoofable); reverse-proxy
deployments get one shared bucket per proxy IP. Logged in the threat
model as accepted risk DA-08, to be revisited when a verified-proxy
config lands.

Also scaffolds development/THREAT_MODEL.md with STRIDE-per-element
methodology, system-context DFD, and Dashboard↔API as the first fully
worked component (7 sub-flows, ~50 threat entries). F1 Authn ships
with 3 threats mitigated: rate limit (new), uniform 401 (verified
already in place), bcrypt length clamp (verified already in place via
Pydantic max_length=72).
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anti
2026-04-23 13:25:28 -04:00
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# 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 | **?** | Verify: production error handler doesn't return tracebacks. |
| 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.
- [ ] Production error handler suppresses tracebacks and internal details.
- [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 |