# Api Security Testing

> Pon a prueba una API REST, GraphQL o gRPC con Strix: agentes autónomos enumeran endpoints y explotan el OWASP API Security Top 10 (2023) con una PoC funcional por cada hallazgo.

Fuente: https://skillsagentes.com/skills/usestrix/strix/api-security-testing
Markdown: https://skillsagentes.com/skills/usestrix/strix/api-security-testing.md

Repositorio: https://github.com/usestrix/strix
Autor: usestrix
Licencia: Apache-2.0
Actualizado: hace 5 días
Coste de contexto: 171 tok instalada, 1.5k tok al activarse, 1.5k tok con todos los archivos del bundle
Bundle: 1 archivo, 6 KB
Permisos que pide: ninguno declarado

## Instalación

Un skill son archivos markdown: los mismos archivos valen para cualquier agente y lo único que cambia es el directorio de destino, es decir la bandera `--agent`. Añade `-g` para instalarlo en todos los proyectos de la máquina.

```bash
# Claude Code
npx -y skills add usestrix/strix --skill api-security-testing --agent claude-code
# Cursor
npx -y skills add usestrix/strix --skill api-security-testing --agent cursor
# Codex
npx -y skills add usestrix/strix --skill api-security-testing --agent codex
# Gemini CLI
npx -y skills add usestrix/strix --skill api-security-testing --agent gemini
# Windsurf
npx -y skills add usestrix/strix --skill api-security-testing --agent windsurf
# Cline
npx -y skills add usestrix/strix --skill api-security-testing --agent cline
```

## Qué hace

- Enumera endpoints de una API a partir de un esquema OpenAPI/GraphQL/Postman o rastreando el API
- Explota vulnerabilidades del OWASP API Security Top 10 (2023) con agentes autónomos de Strix
- Prueba BOLA/IDOR usando dos tenants, y autorización a nivel de función con tokens de bajo y alto privilegio
- Entrega cada hallazgo con una petición de prueba de concepto (PoC) funcional

## Cuándo usarla

- El usuario pide hacer pentest, auditar o buscar vulnerabilidades en una API, endpoint o servicio backend

## Cuándo no

- El objetivo es una app web general en lugar de una API (usa el skill equivalente para apps web)

## Qué la activa

- "Haz un pentest a esta API REST usando el esquema OpenAPI"
- "Busca vulnerabilidades BOLA entre estos dos tenants de mi API"
- "Prueba si un token de usuario normal puede llamar rutas de admin"

## Antes de instalar

- Requiere Strix instalado (Docker + clave LLM, o el token de la nube app.strix.ai), el esquema de la API y credenciales de dos tenants.
- makes network requests

## Archivos

- SKILL.md — 6 KB

## SKILL.md

Reproducido tal cual desde usestrix/strix bajo Apache-2.0. Esta sección es el documento original y está en inglés.

# Security-test an API

APIs fail differently from web UIs: there is no rendered surface to crawl, the interesting bugs are authorization-shaped rather than injection-shaped, and the same endpoint behaves differently per token. This workflow targets those specifics with Strix's autonomous agents, using the current [OWASP API Security Top 10 (2023)](https://owasp.org/API-Security/editions/2023/en/0x11-t10/) as the coverage checklist. For the web-app equivalent, the current edition is the OWASP Top 10:2025 — see **owasp-top-10-testing**.

Install, LLM setup, full CLI flags, and the managed-cloud path are in the **penetration-testing-with-strix** skill. Read it if `strix --version` fails or the target is not an API.

## 1. Gather what the agents need

APIs are near-impossible to test blind, so collect first:

| Input | Why it matters |
|---|---|
| **Schema** — OpenAPI/Swagger file, Postman collection, GraphQL endpoint (introspection), or a gRPC `.proto` | Turns guesswork into full endpoint enumeration. Biggest single win in coverage. An OpenAPI/Swagger or Postman spec (`.json`/`.yaml`/`.yml`) is a target Strix takes directly; a `.proto` is not, so pass it with `--workspace-file`. |
| **Two sets of credentials/tokens**, ideally in different tenants | BOLA/IDOR — API1:2023, still the #1 API risk — can only be *proven* by accessing tenant A's objects with tenant B's token. |
| **A low-privilege and a high-privilege token** | Required to prove broken function-level authorization (API5:2023 — a `user` calling admin-only routes). |
| **Example object IDs** | Lets agents test ID tampering immediately instead of hunting for valid identifiers. |
| **Out-of-scope routes** | Payments, mass notification, destructive admin endpoints. |
| **Rate limits / WAF** in front of the API | Avoids agents burning budget on throttled requests; mention them so testing adapts. |

Ask the user for anything missing — do not fabricate tokens or scan an API they do not own.

## 2. Run the scan

Pass the spec as a **target**, not as prose in the instruction — Strix parses OpenAPI/Swagger (`.json`/`.yaml`) and Postman collection exports directly, so the agents start from the real endpoint list:

```bash
strix -n -t ./openapi.yaml -t https://api.staging.example.com --max-budget 20 \
  --instruction "Tenant A token: <tokenA> (org 1111, user id 11, order id 501).
Tenant B token: <tokenB> (org 2222, user id 22).
Admin token: <tokenAdmin>.
Focus: BOLA across orgs (API1), function-level authz on /admin/* (API5), object property level authz on PATCH /users/{id} — both mass assignment and over-exposed fields in list responses (API3), unrestricted resource consumption (API4).
Out of scope: POST /billing/*, POST /notifications/broadcast."
```

- **Postman instead of OpenAPI:** a collection export works as a target (`-t ./collection.postman_collection.json`), or pull one live with `-t postman://<collection-uuid>` (optionally `"postman://<collection-uuid>?env=<environment-uuid>"`), which needs `POSTMAN_API_KEY` in the environment.
- **Many services at once:** put one target per line in a file and pass `--target-list ./targets.txt`, repeatable and combinable with `-t`.
- **Add the backend source for depth:** `-t ./services/api -t https://api.staging.example.com`. With code access the agents can reason about authorization checks and object ownership rather than inferring them from responses.
- **gRPC:** target the endpoint and pass the definition as a workspace file, `-t https://grpc.staging.example.com --workspace-file ./service.proto`. Only `.json`, `.yaml`, and `.yml` specs are recognized as targets, so `-t ./service.proto` fails with "Path exists but is not a directory".
- **GraphQL:** point at the GraphQL endpoint and say whether introspection is enabled; call out that you want batching/aliasing abuse, depth/complexity limits, and per-field authorization tested.
- **Internal/private APIs** unreachable from your machine: use the managed platform's network connector — see **managed-pentesting-with-strix**.
- Use `--instruction-file` when the credential/context block gets long, and keep tokens out of shell history and out of committed files.
- **Supporting files** the agents should read but not test, such as an endpoint wordlist or handwritten notes about the tenancy model: pass `--workspace-file ./notes.md`. The file lands read-only in `/workspace`. Add `:DEST` to choose the path, for example `--workspace-file ./wordlist.txt:lists/wordlist.txt`.

## 3. Verify findings

`strix_runs/<run>/penetration_test_report.md` first, then `vulnerabilities/*.md` — each contains the exact request that proved the issue. Replay it (for example, with `curl`) before reporting; for authorization findings, confirm the response really contains the other tenant's data rather than an empty 200.

`findings.sarif` uploads to GitHub code scanning; `vulnerabilities.json` is the structured index for ticketing.

## 4. Fix, re-test, and keep it tested

Remediate with **fix-security-vulnerabilities-with-strix** (fix the authorization check, not the single endpoint), then re-run against the same target to prove the exploit is dead. Wire it into pull-request CI with **ci-security-scanning-with-strix** so new endpoints get tested as they ship.

## Dónde encaja

- Categoría: [Seguridad](https://skillsagentes.com/categorias/seguridad.md) — Auditorías, revisión de dependencias, manejo de secretos y modelado de amenazas.
- Creador: [usestrix](https://skillsagentes.com/creators/usestrix.md) — 9 skills en el directorio
- [Todas las skills](https://skillsagentes.com/skills.md)
- [Ranking de instalaciones](https://skillsagentes.com/ranking.md)

## Otras skills del mismo repositorio

- [Penetration Testing With Strix](https://skillsagentes.com/skills/usestrix/strix/penetration-testing-with-strix.md): Pentestea una app web, API, código, repo, URL, dominio o IP con Strix: agentes autónomos que explotan y demuestran vulnerabilidades con PoC, por CLI autoalojada o nube gestionada app.strix.ai.
- [Owasp Top 10 Testing](https://skillsagentes.com/skills/usestrix/strix/owasp-top-10-testing.md): Prueba una aplicación contra el OWASP Top 10:2025 con Strix: agentes de IA que intentan exploits reales y reportan solo lo probado, con PoC.
- [Managed Pentesting With Strix](https://skillsagentes.com/skills/usestrix/strix/managed-pentesting-with-strix.md): Ejecuta un pentest gestionado de una app web o API vía la API REST de app.strix.ai, sin Docker local, clave LLM ni instalación.
- [Web App Penetration Testing](https://skillsagentes.com/skills/usestrix/strix/web-app-penetration-testing.md): Pentestea una app web o sitio de extremo a extremo: testeo de caja negra que encuentra y explota vulnerabilidades reales (auth bypass, IDOR, inyección, XSS, SSRF, lógica de negocio) con Strix.
- [Fix Security Vulnerabilities With Strix](https://skillsagentes.com/skills/usestrix/strix/fix-security-vulnerabilities-with-strix.md): Corrige vulnerabilidades encontradas por un pentest de Strix: clasifica por severidad, parchea la causa raíz y vuelve a escanear para probar el fix.

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