MCP 服务器

The Box

A local MCP daemon that turns an agentic coding client into a bug bounty operator, with 103 tools for offensive security testing including MITM proxy, traffic analysis, and OOB callbacks.

README

<p align="center"> <b>A local MCP daemon that turns an agentic coding client into a bug bounty operator.</b> </p>

The Box is not a chat wrapper around nmap. It is a stateful daemon that owns a MITM proxy, a traffic database, an application graph, an evidence vault, an out-of-band callback server and a local CVE/report knowledge base — and exposes all of it as 103 MCP tools. You point Claude Code (or any MCP client) at it, and the model drives real offensive tooling against targets you authorized, while the daemon enforces scope, rate limits and reporting discipline in code.

The design premise: an LLM is good at deciding what to try next and terrible at not making things up. So every claim the model wants to make has to survive a gate that the daemon controls, not the model.

┌─────────────────┐   MCP over StreamableHTTP    ┌──────────────────────────┐
│  Claude Code    │ ──────────────────────────>  │  boxbridge daemon        │
│  (orchestrator) │ <──────────────────────────  │  127.0.0.1:7070/mcp      │
└─────────────────┘      103 native tools        └───────────┬──────────────┘
                                                             │
      ┌──────────────────────┬───────────────────────┬───────┴───────────┬─────────────────┐
      ▼                      ▼                       ▼                   ▼                 ▼
  MITM proxy           SQLite traffic +          OOB server         Intel RAG        Sandboxed
  (CA, HTTP/1+2,       app graph +               (HTTP + DNS,       (CVE, ExploitDB,  tool runner
  TLS impersonate)     evidence vault            ACME certs)        H1 corpus)        (rate-limited)

What it actually does
Feature tour
Install
Running it
Connecting a client
Configuration
Tool reference
Project layout
Development
Status and limitations
Scope of use
License

What it actually does

Three things a plain MCP tool wrapper does not:

1. It keeps state across the whole hunt. Every request that goes through the proxy, the browser or a replay lands in traffic.db. From that traffic the daemon builds an application graph (endpoints, parameters, edges, staleness), tracks which of 18 attack techniques were already tried against each endpoint, and lets the model ask "what have I not tested yet?" instead of re-scanning blindly.

2. It enforces the rules in code, not in the prompt. A scope guard checks every offensive request against the authorized target list before it leaves the machine. A rate governor caps requests per second per target. A report gate lints drafts against banned hedging phrases and hard-stops any finding that cannot complete the sentence "As an intruder I can ___ by ___, demonstrated by ___". The model cannot talk its way past these — they run in the tool call path.

3. It closes the loop on evidence. Findings attach to a hash-chained evidence vault (Merkle-verifiable), so a report references artifacts that can be proven unmodified since capture.

Feature tour

Recon

Passive and active discovery, each wrapped as a native tool with parsed structured output rather than raw stdout.

Subdomains — subfinder_scan, amass_passive (CT logs, DNS providers, archives)
Historical URLs — waybackurls_discovery, gau_discovery, urlfinder_discovery
Crawling — hakrawler_crawl
Ports — nmap_scan (with -sV), naabu_scan, rustscan_scan, masscan_scan
HTTP probing — httpx_probe (status, title, server, tech fingerprint)
DNS — dnsenum_scan (records + zone transfer attempt)
Content discovery — ffuf_discovery, feroxbuster_discovery, gobuster_discovery, dirsearch_discovery, all with soft-404 baselining
Parameter discovery — arjun_discovery, x8_discovery, paramspider_discovery, param_extract, qsreplace_transform
Fingerprinting — whatweb_fingerprint, wafw00f_detect, identify_stack (aggregates both)
OSINT — censys_host_lookup, censys_webproperty_lookup

Intercepting proxy

A full MITM proxy written from scratch, not a shell-out to Burp.

Own root CA, per-host leaf generation with a cache
HTTP/1.1 and HTTP/2 servers, WebSocket passthrough
TLS impersonation — egress through curl-impersonate so the JA4 fingerprint matches a real Chrome build instead of Node's TLS stack
Everything captured into traffic.db, searchable via history_search
Configurable passthrough host list, client-certificate identities

Replay and fuzzing

repeater_send — replay any captured request with method/path/header/body overrides
intruder — positional payload attacks over a captured request, with draft/run/poll verbs
chain_send — a sequence of requests in one call, feeding each response into the next (CSRF token flows, multi-step state machines)
comparer_diff — side-by-side diff of two captured artifacts
reflected_find — scan captured traffic for a canary, classified by injection context (html_body, html_attribute, js_string, …)
probe_matrix — fire the full 18-technique catalog at one parameter in one call
differential_send — replay one request as several registered identities and emit a mechanical authorization verdict

Authorization testing

Testing authz properly needs more than one session, so identities are first-class:

identity_register / identity_list — victim, attacker, unauth, low_priv, admin
Credentials live in an encrypted vault (argon2 + passphrase), never in tool output
identity_capture_denial — record how the target should deny a request, so a later bypass is provable
differential_send compares responses across identities mechanically

Business logic

Invariants — invariant_register, invariant_check, invariant_mine. Register a property that must always hold ("balance never goes negative", "status only moves forward"), then have the daemon check it against live traffic. Mining proposes candidates from captured history.
Workflows — record a multi-step flow from the browser (workflow_record_start / workflow_record_stop, sliced into steps by page-load events), or reconstruct one retroactively from captured traffic (workflow_from_history). Replay it pure (byte-literal, as a regression baseline) or bound (substituting tokens and cookies from earlier steps) via workflow_replay.
State machine abuse — workflow_mutate runs the recorded flow with a mutation plan: skip a step, repeat one 2–50 times, reorder the permutation, or fire several in parallel. workflow_mutation_analysis classifies what came back into hypotheses.
Race conditions — workflow_race fires a single-packet race on a chosen step to detect TOCTOU and deduplication bypasses
Semantic parameter fuzzing — workflow_semantic_fuzz mutates a parameter using a 50-kind catalog driven by the parameter's inferred meaning, not a generic wordlist

Browser

Chromium via CDP, launched by the daemon or attached to an existing instance
Routed through the MITM proxy, so browser traffic joins the same history
Fingerprint parity work (navigator, WebGL, fonts) to survive bot detection
Evidence capture: screenshots, console, network, DOM snapshots

Out-of-band

A self-hosted Collaborator equivalent:

oob_issue_token mints a callback FQDN; oob_check_hits retrieves callbacks
HTTP and DNS listeners, ACME-provisioned certificates for HTTPS callbacks
A public panel to inspect hits
Detects blind SSRF, blind RCE, blind XXE, blind SQLi

Static analysis

JS bundles — js_analyze: fetch (8 MB cap) → prettier beautify → source-map recovery → AST + regex scanners for endpoints, secrets and dangerous sinks. js_subagent_mine spawns a focused subagent to find what regex misses (constructed strings, base64 blobs, env-gated code).
Mobile — apk_extract (apktool + jadx), ipa_extract (Mach-O encryption info, plists). mobile_endpoint_mine and mobile_subagent_mine pull endpoints and findings out of the artifacts. Optional Frida hooking on a connected device (frida_inventory, frida_trace_class).
GraphQL — graphql_introspect, graphql_take_snapshot (sha256-deduped for temporal diff), graphql_authz_fuzz (synthesizes minimal mutations with placeholder args to probe authorization without executing destructive writes)

Scanners

Wrapped with parsed output and scope enforcement: nuclei_scan (inline custom YAML templates supported), sqlmap_scan, dalfox_scan, xsstrike_scan, wpscan_scan.

Intel RAG

A local knowledge base, hybrid BM25 + vector retrieval with a reranker:

CVE data (NVD), ExploitDB, nuclei templates, CWE catalog
A corpus of disclosed HackerOne reports
ONNX embeddings (bge-m3) served locally, LanceDB vector store, optional GPU
cve_search — keyword search over CVE, ExploitDB and nuclei templates with vendor/product/year/severity filters
h1_similar_reports — find disclosed reports resembling the endpoint being triaged
pattern_match_by_endpoint — cross-source union of historical findings and CWE patterns matching an endpoint signature

Queried mid-hunt, this answers "what has already worked against this exact stack" instead of guessing.

Hunt management

Targets — create_target registers in DRAFT (passive only) until the operator promotes it to active
Hypotheses — a ranked queue of leads; hypothesis_create_suggestion makes the model file a lead instead of asserting a vuln
Coverage ledger — coverage_report answers "what has not been tried", per endpoint and technique
Verdicts — endpoint_verdict_emit records defended / inconclusive / blocked / vulnerable per endpoint
Blockers — blocker_declare prices a blocker (2FA, CAPTCHA, missing credential) instead of silently giving up; blocker_resolve reopens everything that was closed because of it
Notebook — per-target notes with typed mentions
Diff watcher — scheduled snapshots of subdomains, URLs, graph nodes and bundle findings, alerting on change
ROI tracker — imports HackerOne CSV to track what actually paid

Reporting discipline

This is the part the project cares most about.

report_create_from_hypothesis renders from a fixed template
report_lint runs the gate: banned hedging phrases (likely, could, almost certainly, platform-wide compromise), missing sections, unproven chain links
Intruder test — a hard stop. A finding that cannot complete "As an intruder I can ___ by ___, demonstrated by ___" does not render.
program_policy_set records what the program actually pays for, so out-of-scope classes get dropped before effort is spent
Adversarial panel — subagent_spawn with refuter lenses; adversarial_verdict_emit collects votes trying to refute a finding before it ships
session_close_report generates an honest end-of-session summary from the coverage ledgers, including what was left untested

Safety substrate

Scope guard — offensive requests are checked against the active target's authorized scope; DRAFT targets allow passive tools only
Rate governor — per-target request/second and concurrency caps
Sandboxed runner — external binaries run with a per-plugin working directory, hard timeouts and structured JSONL logging
Evidence vault — hash-chained, evidence_vault_verify_chain returns a Merkle root or the exact sequence number where the chain broke

Install

Target platform is WSL2 Ubuntu 24.04. It runs on native Ubuntu too; the Windows host steps below are WSL-specific.

0. Host prerequisites (WSL only, PowerShell as admin)

wsl --status
wsl --install -d Ubuntu-24.04    # if absent
wsl --set-default-version 2

Edit %USERPROFILE%\.wslconfig — the daemon holds embedding models in memory and Chromium plus parallel nuclei runs are not cheap:

[wsl2]
memory=16GB
processors=8
swap=8GB
localhostForwarding=true

Then wsl --shutdown and reopen the Ubuntu terminal.

1. Clone into the Linux filesystem

Not /mnt/c/ — the I/O penalty is severe and SQLite behaves badly across the 9p mount.

git clone https://github.com/horizonfps/the-box-mcp.git ~/the-box
cd ~/the-box

2. Bootstrap the toolchain

chmod +x infra/bootstrap.sh infra/verify.sh
./infra/bootstrap.sh
./infra/verify.sh

bootstrap.sh is idempotent — a second run is mostly skip: lines. It installs:

Source	Contents
apt	build tooling, `nmap`, `masscan`, `dnsenum`, `whatweb`, keyring/secret libs, Chromium runtime deps, JRE (for apktool)
NodeSource	Node 22
Go (pinned 1.23.4, sha256-verified)	`subfinder`, `httpx`, `nuclei`, `naabu`, `katana`, `urlfinder`, `amass`, `waybackurls`, `gau`, `hakrawler`, `ffuf`, `gobuster`, `qsreplace`, `anew`, `dalfox` — all version-pinned
cargo	`rustscan` 2.4.1, `feroxbuster` 2.13.1, `x8` 4.3.2
pipx	`arjun`, `paramspider`, `wafw00f`, `dirsearch`, `uro`, `frida-tools`
direct download	`sqlmap`, nuclei templates, wordlists

Layout it creates:

/opt/thebox/          system-wide
├── bin/              symlinks to installed tools
├── cache/            wordlists, nuclei templates, intel corpora
└── proxy/            proxy support files

~/.thebox/            per-user
├── state/            app.db, traffic.db, sessions, bridge token
├── logs/             rotated logs (bridge, tools, intel)
├── config/           runtime config
└── scratch/          per-target working directories

verify.sh is the gate: exit 0 means the environment is good.

3. Install Node dependencies

corepack enable
pnpm install

Native modules (better-sqlite3, argon2, onnxruntime-node, @lancedb/lancedb) compile here. This is the step most likely to need build tooling that step 2 already installed.

4. Optional components

Each is independent — skip what you do not need.

./infra/proxy-ca-install.sh              # trust the MITM root CA locally
./infra/proxy-impersonate-install.sh     # curl-impersonate for Chrome JA4 parity
./infra/browser-install.sh               # Chromium for the CDP browser module
./infra/oob-public-listen-install.sh     # public OOB listeners (needs a domain + open ports)
./infra/oob-public-cert-sync.sh          # ACME certificates for HTTPS callbacks
sudo ./infra/systemd/install-templates-timer.sh   # nightly nuclei template refresh

The intel RAG needs a one-time corpus build (downloads and embeds; expect it to take a while and to want a GPU if you have one):

node engine/scripts/intel-ingest.mjs
node engine/scripts/intel-embed-setup.mjs
node engine/scripts/intel-embed.mjs

Running it

cd ~/the-box
pnpm bridge

The daemon binds 127.0.0.1:7070, writes its bearer token to ~/.thebox/state/bridge-token and its port to ~/.thebox/state/bridge-port. A PID lockfile prevents a second instance from corrupting the SQLite databases.

For a long-lived session detached from the terminal:

setsid nohup pnpm bridge > ~/.thebox/bridge.log 2>&1 < /dev/null & disown

Production build (bundles to a single ESM file, ~50 KB plus node_modules):

pnpm build && pnpm start

Inference credentials

Some tools run their own inference inside the daemon — subagent_spawn, js_subagent_mine, mobile_subagent_mine, the adversarial review panel. Those need an Anthropic-compatible endpoint:

export ANTHROPIC_BASE_URL="https://api.anthropic.com"
export ANTHROPIC_AUTH_TOKEN="<your token>"

Any Anthropic-compatible proxy works in place of the official endpoint. Tools that do not spawn subagents run fine without these set.

Connecting a client

Add the daemon to your MCP client. For Claude Code, in .mcp.json:

{
  "mcpServers": {
    "thebox": {
      "type": "http",
      "url": "http://127.0.0.1:7070/mcp",
      "headers": { "Authorization": "Bearer ${THEBOX_BRIDGE_TOKEN}" }
    }
  }
}

export THEBOX_BRIDGE_TOKEN="$(cat ~/.thebox/state/bridge-token)"

Two meta-tools bracket every session:

box_targets — list authorized targets and show which is active
box_use_target — set the active target; the scope guard and the per-target rate limit key off this

Nothing offensive runs until a target is active. A typical opening:

box_use_target { "target": "example.com" }
coverage_report {}                       → what has not been tried
hypothesis_list {}                       → the ranked lead queue

Restarting the daemon drops the MCP connection: reconnect in the client and call box_use_target again, since the active target resets.

Configuration

Everything is env-driven. Defaults are sane; the ones worth knowing:

Variable	Default	Purpose
`THEBOX_BRIDGE_HOST`	`127.0.0.1`	Bind address. Leave it local.
`THEBOX_BRIDGE_PORT`	`7070`	Daemon port
`THEBOX_STATE_DIR`	`~/.thebox/state`	Databases, token, sessions
`THEBOX_LOGS_DIR`	`~/.thebox/logs`	Bridge, tool and intel logs
`THEBOX_SCRATCH_DIR`	`~/.thebox/scratch`	Per-target working directories
`THEBOX_PROXY_PASSTHROUGH_HOSTS`	—	Hosts the MITM proxy must not intercept
`THEBOX_PROXY_IMPERSONATE_BIN`	—	Path to `curl-impersonate` for TLS parity
`THEBOX_BROWSER_MODE` / `THEBOX_BROWSER_CDP_URL`	—	Launch a browser or attach to one
`THEBOX_OOB_PUBLIC_DNS_BIND`	—	Bind address for the public DNS listener
`THEBOX_OOB_PUBLIC_TRUSTED_PROXY`	—	Upstream proxy allowed to set forwarded headers
`THEBOX_INTEL_EMBED_GPU`	`0`	GPU acceleration for embeddings
`THEBOX_INTEL_LANCE_DIR`	under state dir	Vector store location
`THEBOX_ADVERSARIAL_REVIEW`	on	Adversarial refuter panel before a finding ships
`THEBOX_TOOL_LOOP_MAX_ITER`	`0` (unlimited)	Cap on the internal tool loop
`NVD_API_KEY`	—	Higher NVD rate limit during intel ingest
`WPSCAN_API_TOKEN`	—	WPScan vulnerability database

Full list: grep -rhoE 'THEBOX_[A-Z0-9_]+' engine/src | sort -u.

Tool reference

103 tools total — 101 native plugins plus box_targets and box_use_target. Each plugin lives in engine/src/tools/native/<name>/index.ts with a JSON Schema validated by ajv at registration and at every call.

Adding one is three steps: create the directory with an index.ts default- exporting a ToolPlugin, add one import and one array entry in engine/src/tools/native/loader.ts, restart. The loader uses static imports deliberately — plugins must share the boxbridge/persistence/db.ts singleton with the bootstrap, which separate bundler entry points would duplicate. See engine/src/tools/native/README.md.

The daemon prints the full roster on boot:

[boxbridge] loaded 101 tools (adversarial_verdict_emit, amass_passive, apk_extract, ...),
            manifestTokens=5075 fullSchemaTokens=26269

Descriptions are what steer the model, so they carry the intent and the preconditions, not just the signature.

Project layout

engine/src/
├── boxbridge/      daemon: HTTP + MCP server, auth, sessions, persistence, routes
├── tools/
│   ├── native/     101 tool plugins, one directory each
│   ├── runner.ts   sandboxed external-binary runner (rate limit, timeout, JSONL log)
│   └── ...
├── proxy/          MITM: CA, leaf certs, HTTP/1, HTTP/2, WS, TLS impersonation
├── history/        traffic capture, search, replay
├── appGraph/       endpoint/parameter graph built from traffic
├── intruder/       positional payload attacks
├── repeater/       request replay with overrides
├── comparer/       artifact diffing
├── reflected/      canary reflection finder with context classification
├── probe/          18-technique probe matrix
├── chain/          multi-step request chains
├── bizlogic/       race conditions, state machines, semantic fuzzing
├── invariants/     invariant registration, checking, mining
├── identities/     test identities and credential vault
├── browser/        CDP control, stealth, evidence capture
├── oob/            out-of-band HTTP + DNS server, ACME, public panel
├── jsBundle/       JS bundle download, beautify, source-map recovery, scanners
├── mobile/         APK/IPA extraction and analysis, Frida integration
├── graphql/        introspection, snapshots, authz fuzzing
├── intel/          RAG: ingest, chunk, embed, BM25 + vector retrieval, rerank
├── evidence/       capture and hash-chained vault
├── hypotheses/     lead queue, ranking, lints
├── coverage/       technique coverage ledger
├── reports/        rendering, lint gate, intruder test, export
├── programPolicy/  what the program pays for; opening gate
├── adversarial/    refuter panel and verdicts
├── subagents/      focused subagent spawning and finding emission
├── diffWatcher/    scheduled surface snapshots and change alerts
├── notebook/       per-target notes with typed mentions
├── roi/            bounty ROI tracking, HackerOne CSV import
├── ops/            scope guard, rate governor, blockers, audit log
└── prompts/        system prompt modules and rules

infra/              bootstrap, verification, optional installers, systemd units
engine/scripts/     smoke tests, intel pipeline, maintenance scripts

Development

pnpm test                        # full suite: 4251 tests, 697 suites, ~5 min
pnpm test:orphans                # find test files the runner does not pick up
pnpm build                       # tsup bundle → engine/dist/bootstrap.js
node engine/scripts/smoke-<area>.mjs   # per-area smoke tests

Smoke scripts exist per subsystem (smoke-browser, smoke-oob-public, smoke-evidence-vault, smoke-graphql-deep, smoke-mobile, …) and run against the real daemon rather than mocks.

pnpm typecheck runs tsc in strict mode over the daemon surface and currently reports around 70 errors — mostly test doubles that do not satisfy full playwright interfaces, unused locals, and a handful of nullability gaps. They do not affect the build (tsup transpiles without type checking) or the test suite, which is green. It is standing debt, not a gate.

Comments and identifiers are English. Some inline comments and prompt content are still Portuguese from earlier iterations.

Status and limitations

Honest accounting, since the project's whole premise is not overclaiming:

Memory. The daemon starts around 4.5 GB RSS because the embedding model loads twice — a known debt. Each intel query adds roughly 1.17 GB, which saturates rather than leaks. Budget accordingly, or skip the intel corpus.
Restart cost. Restarting drops MCP clients and resets the active target.
Single instance. A PID lockfile enforces one daemon per state directory.
Platform. Developed and tested on WSL2 Ubuntu 24.04. Other Linux distributions should work; macOS and Windows-native are untested.
Optional tools soft-fail. If a binary is missing the tool returns {ok: false, error: ...} instead of crashing the daemon. masscan needs root or CAP_NET_RAW. Frida needs a connected device.
A prior desktop UI is not part of this repository. The Box began as a Tauri application with its own chat interface; it was rebuilt as an MCP daemon so that an existing agentic client does the orchestration. Some module names and comments still carry traces of that era.

Operational notes

Things worth knowing before you run this on your own machine.

Keep the daemon local. It binds 127.0.0.1 for a reason. The bearer token in ~/.thebox/state/bridge-token is the only thing between a caller and the full toolchain.
The proxy has a root CA. Its private key sits under ~/.thebox/state/. Installing that CA into a trust store makes the machine trust anything the proxy signs — do it on your hunting box, not on a shared one.
traffic.db is not yours. It holds full request and response bodies from targets, authenticated sessions included. It does not belong in a repository, in a backup you do not control, or pasted into a report.
Credentials are encrypted at rest (argon2 + your passphrase) and tools return a reference, never the secret.
bash_exec runs arbitrary commands as the daemon user. The sandbox bounds the working directory and the timeout, not the capability.

Scope of use

This is offensive tooling. It sends real traffic to real hosts.

Use it only against systems you own or are explicitly authorized to test — a bug bounty program whose published scope covers the target, a signed engagement, or your own lab. The scope guard, the DRAFT-by-default target state and the rate governor keep an authorized engagement inside its boundaries; they are not a substitute for the authorization itself.

You are responsible for what you point this at.

License

MIT. See LICENSE.