@cyanheads/pentest-mcp-server
Offline methodology engine and payload workshop for authorized penetration testing, CTF, security research, and education via MCP. STDIO or Streamable HTTP.
7 Tools
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**Public Hosted Server:** [https://pentest.caseyjhand.com/mcp](https://pentest.caseyjhand.com/mcp)
---
> **Authorized use only.** This server is designed for penetration testers, red teamers, CTF players, security researchers, and students working on systems they own or have explicit written authorization to test. Users are solely responsible for ensuring their testing is lawful and appropriately scoped. Unauthorized access to computer systems is illegal — this server does not and cannot enforce authorization on your behalf.
>
> **Dual-audience design.** Every offensive technique is paired with detection indicators and mitigations. Blue teamers, developers, and anyone building detection coverage will find the methodology and ATT&CK data as useful as the red team workflows.
---
## Overview
An offline methodology engine for authorized penetration testing, CTFs, and security research, built on MITRE ATT&CK, the OWASP Testing Guide, and annotated payload templates. Generate a phased test plan, map techniques to a target, analyze HTTP responses for leaks, and generate or encode payloads, each paired with detection and mitigation context.
### Tools
| Tool | Description |
|:-----|:------------|
| `pentest_get_guide` | Step-by-step authorized-testing methodology playbook for a chosen attack vector, phase-filterable, with detection and mitigation per technique. |
| `pentest_analyze_response` | Analyzes raw HTTP response headers/body from authorized probing for leakage, fingerprinting, and misconfiguration. |
| `pentest_lookup_technique` | Looks up a MITRE ATT&CK technique by ID or keyword, with detection data, mitigations, and procedure examples. |
| `pentest_lookup_group` | Looks up a MITRE ATT&CK threat group or software entry by ID or name, with aliases and technique usage. |
| `pentest_map_techniques` | Ranks ATT&CK techniques and OWASP test cases against a target profile (stack, services, auth type, OS). |
| `pentest_generate_payloads` | Generates annotated payload templates for a vulnerability category and injection context, with optional WAF bypass variants and encoding. |
| `pentest_encode_payload` | Applies an ordered encoding chain to a payload string with decode-path tracing. |
## Capability reference
### `pentest_get_guide` tool
- `vector`: `auth_bypass`, `idor`, `ssrf`, `xss`, `sqli`, `xxe`, `path_traversal`, `cors`, `csrf`, `open_redirect`, `deserialization`, `race_condition`, `ssti`, `command_injection`, or `jwt_attack`; `phase`: `all` (default), `recon`, `enumeration`, `exploitation`, or `post_exploitation`
- Playbook techniques carry `detection` and `mitigation`, with `owasp_references`, `attack_technique_ids`, and context-derived `nextToolSuggestions`
- Optional `target_context` (`stack`, `waf`, `recon_notes`) narrows the playbook
---
### `pentest_analyze_response` tool
- Supply `response_headers` (≤20,000 characters), `response_body` (≤10,000 characters), or both; optional `status_code` (100–599) and `context` (≤2,000 characters). Missing both response fields returns `no_input`
- Findings carry `category`, `severity` (`info`/`low`/`medium`/`high`), `detection`, and `remediation`, ordered by severity descending
- `fingerprints` (`server_software`, `framework`, `language`, `database`, `cloud_provider`, `other`) and `nextToolSuggestions` support follow-up calls
---
### `pentest_lookup_technique` tool
- Supply an ATT&CK ID (`T1190`, `T1059.001`) or keyword; `include_subtechniques` defaults to `true`
- Returns tactics, platforms, description, `detection` (`summary`, `data_sources`, `indicators`), mitigations, procedure examples, and `attack_version`
- Returns `no_match` when the ID or keyword resolves to nothing
---
### `pentest_lookup_group` tool
- Supply an ATT&CK group ID (`G0007`), software ID (`S0002`), or name/keyword; returns `no_match` when nothing resolves
- `type` distinguishes `group` from `software`; results include `aliases`, `description` (≤800 characters), and `attack_version`
- `techniques_used` returns up to 20 techniques with procedure context and `technique_id` for `pentest_lookup_technique`
---
### `pentest_map_techniques` tool
- Supply at least one of `stack`, `services`, `auth_type` (`jwt`/`session_cookie`/`api_key`/`oauth2`/`basic_auth`/`ntlm`/`kerberos`/`none`/`unknown`), or `os` (`linux`/`windows`/`macos`/`unknown`); otherwise returns `no_profile`
- `ranked_techniques` carries `relevance_score`, `relevance_rationale`, `detection_opportunity`, `mitigation_summary`, and optional `pentest_guide_vector`; `owasp_test_cases` returns up to 10 cases
- `limit` caps techniques at 1–50 (default 15); enrichment (`truncated`, `shown`, `cap`) discloses the cap
---
### `pentest_generate_payloads` tool
- `category`: `xss`, `sqli`, `ssrf`, `xxe`, `path_traversal`, `ssti`, `command_injection`, `open_redirect`, `csrf`, `deserialization`, `jwt`, `ldap_injection`, `nosql_injection`, or `http_header`; `injection_context`: `html_attribute`, `html_body`, `js_string`, `js_template`, `js_script_block`, `url_parameter`, `url_path`, `sql_where`, `sql_integer`, `xml_element`, `xml_attribute`, `http_header`, `json_value`, `cookie_value`, `file_name`, or `generic`
- `count` caps templates at 1–20 (default 5); each carries `detection_signature` and `mitigation`, with optional `encoding` applied to every template
- `waf_profile`: `cloudflare`, `aws_waf`, `modsecurity_crs`, `imperva`, `akamai`, `f5_bigip_asm`, `nginx_modsecurity`, `fortinet_fortiwaf`, `none` (default), or `unknown`; profiles other than `none` add `waf_bypass_note`
---
### `pentest_encode_payload` tool
- `payload` accepts up to 10,000 characters; `chain` applies 1–6 steps left to right from `url`, `double_url`, `html_entity`, `unicode`, `hex`, `base64`, `js_escape`, `null_byte`, `mixed_case`, or `comment_break`
- Returns `intermediate_steps` and `detection_note`; `explain` (default `true`) adds `decode_path` and `bypass_rationale`
- Returns `encoding_error` when a transform fails
---
## Features
Built on [`@cyanheads/mcp-ts-core`](https://github.com/cyanheads/mcp-ts-core): stdio and Streamable HTTP transports, pluggable auth (`none` / `jwt` / `oauth`), swappable storage (`in-memory`, `filesystem`, `Supabase`, `Cloudflare KV/R2/D1`), structured logging with optional OpenTelemetry tracing.
Methodology-specific:
- Fully offline at runtime — no external API calls, no credentials required; all data loaded at startup, zero I/O during request handling
- MITRE ATT&CK Enterprise embedded at build time via `scripts/refresh-attack.ts` and indexed in memory by ID/keyword; fails fast with an actionable error if the data file is missing
- OWASP Testing Guide methodology and payload template library curated as structured TypeScript modules, one per vector/category
- WAF bypass variants keyed by WAF product and attack vector, referencing public research
- All tools annotated `readOnlyHint: true`, `openWorldHint: false` — deterministic output from a bounded embedded dataset
Agent-friendly output:
- `authorized_use_reminder` rendered as the first line of `content[]` on every guide/payload/encoding response — consistent framing regardless of which surface a client forwards
- Techniques and payloads require detection and mitigation context; response findings require `detection` and `remediation`
- `attack_version` echoed on every ATT&CK-backed response so callers can reason about data vintage
- `nextToolSuggestions` pre-filled with arguments derived from the current context, reducing agent planning overhead
- [pentest-guide](skills/pentest-guide/SKILL.md) supports response-evidence review and ATT&CK detection coverage assessment; available through plugin installs and the MCP resource `skill://pentest-guide/SKILL.md`
---
## Build-time data step
The server embeds MITRE ATT&CK Enterprise data (~20 MB JSON) fetched by a one-time script into a gitignored path. **Self-hosters and Docker builders must run this step before the server will start:**
```sh
bun run scripts/refresh-attack.ts
```
This downloads the latest ATT&CK Enterprise JSON from the MITRE GitHub release endpoint, writes it to `src/data/attack/enterprise.json` (gitignored), and updates `src/data/attack/version.ts` with a version string such as `Enterprise v16.1`. The version file is committed; the JSON is not (too large for git history).
**The Dockerfile handles this automatically** — the build stage runs `scripts/refresh-attack.ts` before the TypeScript compile, so `docker build` produces a self-contained image.
If you clone the repo and skip this step, `attack-service` will fail fast at startup with an actionable error message pointing to `scripts/refresh-attack.ts`.
Run the script quarterly (or before each release) to pull the latest ATT&CK version.
---
## Getting started
Connect to the hosted instance:
```sh
claude mcp add --transport http pentest-mcp-server https://pentest.caseyjhand.com/mcp
```
Or run it locally:
```sh
claude mcp add pentest-mcp-server -- npx -y @cyanheads/pentest-mcp-server
```
For other clients, add this to the MCP config file:
```json
{
"mcpServers": {
"pentest-mcp-server": {
"command": "npx",
"args": ["-y", "@cyanheads/pentest-mcp-server"]
}
}
}
```
No API keys required. For Docker or a source build, see [Running the server](#running-the-server).
---
## Configuration
No API keys required. The server is fully offline at runtime.
| Variable | Description | Default |
|:---------|:------------|:--------|
| `MCP_TRANSPORT_TYPE` | Transport: `stdio` or `http`. | `stdio` |
| `MCP_HTTP_PORT` | Port for HTTP server. | `3010` |
| `MCP_AUTH_MODE` | Auth mode: `none`, `jwt`, or `oauth`. | `none` |
| `MCP_LOG_LEVEL` | Log level: `debug`, `info`, `notice`, `warning`, `error`. | `info` |
| `PENTEST_ENABLE_PAYLOAD_GENERATION` | Enable `pentest_generate_payloads` and `pentest_encode_payload`; when `false` they are hidden from clients. | `true` |
| `LOGS_DIR` | Directory for log files (Node.js only). | `/logs` |
| `OTEL_ENABLED` | Enable OpenTelemetry instrumentation (spans, metrics, completion logs). | `false` |
| `LOG_TOOL_FAILURE_PAYLOADS` | Log failed-call arguments and results (key names redacted; free-form values can still contain secrets). | `false` |
| `OTEL_EXPORTER_OTLP_LOGS_ENDPOINT` | OTLP log export destination. | — |
See [`.env.example`](./.env.example) for the full list of optional overrides.
With `PENTEST_ENABLE_PAYLOAD_GENERATION=false`, the two payload tools are absent from MCP discovery and calls.
---
## Running the server
### Local development
Requires [Bun v1.4.0](https://bun.sh/) or higher (or Node.js v24+), with ATT&CK data seeded before startup.
```sh
git clone https://github.com/cyanheads/pentest-mcp-server.git
cd pentest-mcp-server && bun install
cp .env.example .env
```
- **Build and run:**
```sh
# Seed ATT&CK data (first time, or to update)
bun run scripts/refresh-attack.ts
# Build
bun run rebuild
# Run
bun run start:stdio
# or
bun run start:http
```
- **Run checks and tests:**
```sh
bun run devcheck # Lint, format, typecheck, security audit
bun run test # Vitest test suite
bun run lint:mcp # Validate MCP definitions
```
### Docker
```sh
# Build — ATT&CK data is fetched during the build stage
docker build -t pentest-mcp-server .
docker run --rm -p 3010:3010 pentest-mcp-server
```
The Dockerfile defaults to HTTP transport, stateless session mode, and logs to `/var/log/pentest-mcp-server`. OpenTelemetry peer dependencies are installed by default — build with `--build-arg OTEL_ENABLED=false` to omit them. The ATT&CK data refresh runs automatically in the build stage.
---
## Project structure
| Directory / File | Purpose |
|:-----------------|:--------|
| `src/index.ts` | `createApp()` entry point — registers tools and initializes services. |
| `skills/pentest-guide/` | Published response-evidence and ATT&CK coverage guide, also served as an MCP resource. |
| `src/services/attack/` | MITRE ATT&CK service — loads and indexes the embedded enterprise JSON at startup. |
| `src/services/methodology/` | OWASP Testing Guide methodology service — vector branches for `pentest_get_guide`. |
| `src/services/payload/` | Payload template service — keyed by category and injection context. |
| `src/services/encoding/` | Encoding chain executor — pure TypeScript transforms. |
| `src/services/response-analysis/` | Pattern library for information leakage and fingerprinting detection. |
| `src/mcp-server/tools/definitions/` | Tool definitions (`*.tool.ts`) — one file per tool. |
| `src/data/attack/` | `enterprise.json` (gitignored, fetched by `scripts/refresh-attack.ts`) + committed `version.ts`. |
| `src/data/owasp/` | Curated OWASP TG v4.2 methodology content as TypeScript modules. |
| `src/data/payloads/` | Annotated payload templates by vulnerability category. |
| `src/data/waf-bypass/` | WAF bypass variants keyed by product and attack vector. |
| `src/data/encodings/` | Encoding transform functions. |
| `src/data/patterns/` | Regex patterns and metadata for response leakage detection. |
| `scripts/refresh-attack.ts` | Downloads ATT&CK Enterprise JSON and updates the version string. Run once after cloning, then quarterly. |
| `scripts/copy-attack.ts` | Copies the seeded ATT&CK dataset into `dist/` after compilation. |
| `tests/` | Unit and integration tests mirroring `src/`. |
| `docs/design.md` | Design document — tool surface, data strategy, and architectural decisions. |
---
## Development guide
See [`CLAUDE.md`](./CLAUDE.md) for development guidelines and architectural rules. The short version:
- Handlers throw and the framework catches; catch only to translate an owned operational failure into a declared `ctx.fail` contract
- Use `ctx.log` for request-scoped logging and keep request handling stateless and deterministic
- Register new tools via the barrel in `src/mcp-server/tools/index.ts`
- External source boundary: validate raw data, normalize to a domain type, then return the output schema; never fabricate missing fields
- `authorized_use_reminder` is a required output field on every tool that produces methodology or payload content — render it as the first line of every `content[]` response in `format()`
- Keep detection and mitigation context required on techniques and payloads, and `detection` and `remediation` required on response findings
---
## Contributing
Issues are welcome. Run checks and tests before submitting:
```sh
bun run devcheck
bun run test
```
---
## License
Apache-2.0 — see [LICENSE](LICENSE) for details.