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Web Exposure MCP

by Perufitlife

MCP server that confirms publicly served secret files on live URLs by fetching and fingerprinting response bytes.

Install Web Exposure MCP

Pick your client, then add it in one click or paste the config.

STDIONode.js
~/Library/Application Support/Claude/claude_desktop_config.json
claude_desktop_config.json
{
  "mcpServers": {
    "perufitlife-web-exposure-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "web-exposure-mcp"
      ]
    }
  }
}

Settings → Developer → Edit Config, merge this into mcpServers, then fully quit and reopen Claude Desktop.

We couldn’t confirm it starts correctly

We ran the install command but it didn't respond within our test window — this can mean a slow first-time install rather than a real problem.

npx -y web-exposure-mcp

No response to initialize.

This is an experimental automated check and can have false negatives — missing environment variables, a slow cold install, etc. It doesn’t necessarily mean something’s wrong. Last checked 1mo ago.

Overview

web-exposure-mcp probes a deployed URL for exposed files such as .git, .env, source maps, backups, directory listings, and dotfiles. It validates response content to avoid false positives from SPA catch-all pages and returns evidence for confirmed findings. The scanner is read-only, follows no redirects to other hosts, and reads at most 64 KB per file.

Use cases

  • Audit a live deployment for publicly served secret files
  • Confirm whether an exposed .git or .env file is genuinely reachable
  • Check deployed applications for source maps, backups, and SQL dumps
  • Detect directory listings and sensitive dotfiles
  • Run targeted exposure checks in CI with the one-shot CLI

Key features

  • Scans live URLs through the scan_web_exposure MCP tool
  • Lists available checks with list_exposure_checks
  • Validates content using file fingerprints and magic bytes
  • Supports filtering checks with the only parameter
  • Returns findings with severity, paths, and evidence
  • Runs locally with zero dependencies and no API key

Tools2

What Web Exposure MCP lets your agent do. Expand a tool for its parameters.

Self-reported~67 tokens of context

Security & health

What it can reach and how reliably it runs — from our own checks, not the maintainer’s claims.

ActiveLast checked 1d ago

Recent health check succeeded.

13/16 checks healthy over the last 91d

Supply-chain signal

No high-severity advisories surfaced by our automated scan.

Critical 0High 0Medium 0Low 0

Scanned 6d ago via OSV.dev · web-exposure-mcp (npm)

Adoption & maintenance

Factual signals from GitHub, npm, and our automated checks — not a rating.

GitHub stars1Stargazers on the source repository.
npm downloads54Package downloads in the last 30 days.
Last commit4mo agoMost recent push to the default branch.
Install checkInconclusiveDidn't respond in our test window — often a slow first install.
Tools exposed2Callable tools this server registers over MCP.
Directory activity1 viewsConfig copies, upvotes, and views on AllMCPs.

From the project README

web-exposure-mcp

An MCP server that lets an AI agent point at a live deployed URL and confirm whether sensitive files are actually being served to the public — exposed .git, .env secrets, JavaScript source maps, backup/SQL dumps, directory listing, and dotfiles — by fetching the bytes and validating the content. Other tools give you a checklist of maybes; this reports only what is genuinely reachable, with evidence.

⚡ Run it in one line, no install, no API key:

Terminal
npx web-exposure-mcp        # MCP server (stdio) for your AI client
npx -p web-exposure-mcp web-exposure-scan --url https://your-site.com   # one-shot CLI

🤝 Want it done for you? Fixed-scope external-exposure audit — $99 / 24h: I verify every finding live and send a written report with the exact fixes and which credentials to rotate.

npm downloads license node deps

Code
$ npx -p web-exposure-mcp web-exposure-scan --url https://demo.example.com
2 critical, 2 high, 1 medium — 5 CONFIRMED via anonymous fetch (39 requests)
  CRITICAL  /.git/config   valid .git served — full source history downloadable
  CRITICAL  /.env          5 env vars served — API_KEY, DATABASE_URL, JWT_SECRET…
  HIGH      /main.js.map   valid source map — 142 original sources reconstructable
  HIGH      /backup.sql    SQL dump content served
  MEDIUM    /uploads/      directory listing enabled (Index of /uploads)

Why this exists

Publicly-served .git and .env files are routinely called one of the most common high-impact findings in external attack-surface management — Acunetix, Invicti and Legba all ship dedicated detections, and live HackerOne reports for exposed .git/.env are filed continuously. June 2026 saw record leaked-credential dumps, a large share sourced from live, misconfigured servers rather than breached databases.

The MCP ecosystem already covers SSL, CORS, security-headers, SEO audits, and code/commit secret scanning (GitHub MCP, GitGuardian) — but no MCP server probes a deployed URL for publicly-served secret files. This fills that gap: your agent can audit the live edge of any deployment, the way an attacker actually sees it.

The hard part isn't requesting /.env — it's avoiding false positives. Most modern sites answer 200 OK with index.html for every unknown path (SPA catch-all). web-exposure-mcp therefore reads the bytes and fingerprints the content (e.g. .git/config must parse as a git config, .env must contain KEY=VALUE secret lines, an archive must start with the real magic bytes) — so it flags facts, not guesses.

Tools (MCP)

ToolWhat it does
scan_web_exposureProbe a live URL and return only the secret files genuinely served, with evidence. Args: url (required), only (optional check filter), timeout_ms.
list_exposure_checksList every check id, severity and the paths it probes — feed ids into only.

What it confirms

Check idSeverityConfirmed by
git_exposedcritical/.git/config parses as a git config, or /.git/HEAD is a valid ref/sha
env_exposedcriticaldotenv served with ≥2 KEY=VALUE secret lines (not HTML)
source_maphigh.js.map parses as a source map with a sources[] array
backup_artifacthighSQL-dump fingerprints, or ZIP/gzip magic bytes in the body
directory_listingmediumthe autoindex signature (Index of /…) is returned
dotfile_servedhigh.htpasswd hashes, .npmrc/.netrc tokens, .aws/credentials, .ssh/id_rsa, .DS_Store, docker auth

Every check fires at most once and only when the served bytes prove it. Read-only: the scanner never writes anything to the target, follows no redirects into other hosts, and reads at most 64 KB per file (so it fingerprints a multi-GB backup without downloading it).

Add to your AI client

Claude Desktop / Cursor / any MCP client — add to your mcpServers config:

config.json
{
  "mcpServers": {
    "web-exposure": {
      "command": "npx",
      "args": ["-y", "web-exposure-mcp"]
    }
  }
}

Then ask your agent: “Scan https://staging.myapp.com for publicly exposed secret files.”

CLI usage

bash
# Probe a live deployment
npx -p web-exposure-mcp web-exposure-scan --url https://your-site.com

# Run only specific checks
npx -p web-exposure-mcp web-exposure-scan --url https://your-site.com --only git_exposed,env_exposed

# Tighter per-request timeout
npx -p web-exposure-mcp web-exposure-scan --url https://your-site.com --timeout 8000

Output is JSON on stdout (pipe into CI) and a one-line summary on stderr.

Install (optional)

Terminal
npm i -g web-exposure-mcp
web-exposure-mcp                       # start the MCP server (stdio)
web-exposure-scan --url https://site.com   # one-shot scan

Zero dependencies, pure Node ≥18. Every request goes straight from the tool to the target you name — nothing leaves your machine.

Sister tools

Same active-probe philosophy — confirm the real issue by fetching it, not by trusting a checklist. All MIT:

supabase-security · strapi-security · pocketbase-security · firebase-security · appwrite-security · nhost-security

License

MIT © Renzo Madueno


📚 Part of Awesome Backend Security Auditors — the full collection of keyless active-probe auditors.

Reviews

No reviews yet — be the first to share how it worked for you.

Frequently Asked Questions about Web Exposure MCP

It checks for exposed Git metadata, dotenv files, JavaScript source maps, SQL or archive backups, directory listings, and sensitive dotfiles such as .npmrc, .netrc, AWS credentials, SSH keys, and Docker auth files.

It fetches and fingerprints response bytes. For example, .git/config must parse as Git configuration, .env must contain secret-like KEY=VALUE lines, and archives must contain valid magic bytes.

No. It is read-only, never writes to the target, does not follow redirects into other hosts, and reads at most 64 KB per file.

No.

The README provides configuration examples for Claude Desktop and Cursor, and states that it works with any MCP client.

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