dotenv-exposure-check

Probe any live URL for the secret artifacts that get served by accident — .env, .env.production, the .git/ directory, production source maps (.js.map), .DS_Store, and backup/database dumps — and prove each hit by fetching the bytes and showing the real credentials, remote URLs, and source paths inside. Other scanners read your repo; this checks what your server is actually handing to strangers.

⚡ Run it in one line, no install, no token:

npx dotenv-exposure-check --url https://your-app.example.com

🤝 Want it done for you? Fixed-scope audit — $99 / 24h: I verify each exposure live, help you rotate the leaked credentials, and send a written remediation report.

$ npx dotenv-exposure-check --url https://app.example.com
2 critical, 1 high, 1 medium — 4 CONFIRMED by fetching the bytes
  CRITICAL  /.env            5 vars readable — secret keys: DATABASE_URL, STRIPE_SECRET_KEY, JWT_SECRET
  CRITICAL  /.git/config     repo cloneable — remote https://<credentials-redacted>@github.com/acme/app.git
  HIGH      /main.js.map     12 source files mapped (original source embedded)
  MEDIUM    /.DS_Store       directory listing leaked

Why this exists

Serving a secret file is the single highest-yield mistake on the web, and it happens constantly: researchers catalogued 12M+ exposed .env files in the wild, and Palo Alto Unit 42 documented an extortion campaign that scanned 230M targets and harvested 90,000+ secret variables from misconfigured .env endpoints. Source maps are just as bad — even Claude Code shipped a production .js.map leak in 2026 — and a web-readable .git/ folder lets anyone clone your entire source, remote token included.

The hard part is confirmation. Most single-page apps return 200 OK with index.html for every path, so "got a 200 on /.env" means nothing. dotenv-exposure-check fetches each candidate and inspects the actual bytes: an .env hit must contain real KEY=VALUE assignments, a source map must be valid sourcemap JSON, a .DS_Store must carry the Bud1 magic, a backup must have a real archive/dump signature. You triage facts, not 200s.

What it checks

Check	Severity	How it's confirmed
.env / .env.production / .env.local … served	critical	body parsed for KEY=VALUE lines; secret-looking keys (DB/API/JWT/Stripe/AWS) flagged
Exposed .git/ directory (repo cloneable)	critical	/.git/config + /.git/HEAD validated as git stanzas; embedded remote credentials detected and redacted
Production source map (.js.map) exposed	high	parsed as sourcemap JSON (version + mappings); counts mapped sources, flags embedded original source
Backup / database dump downloadable	high	archive (zip/gzip) or SQL-dump signature in the bytes
.DS_Store directory listing	medium	Bud1 binary magic at offset 4

SPA catch-all (200 + index.html for everything) is explicitly rejected, so the tool does not false-positive on modern frontends.

Usage

# Probe a live site (tries the common filenames for each artifact)
npx dotenv-exposure-check --url https://app.example.com

# Restrict to specific candidate paths
npx dotenv-exposure-check --url https://app.example.com --paths .env,.env.production

# Write a shareable HTML report
npx dotenv-exposure-check --url https://app.example.com --html report.html

# Dry run: list what would be checked, send no requests
npx dotenv-exposure-check --url https://app.example.com --no-probe

Output is JSON on stdout (pipe it into CI) and a one-line summary on stderr. Exit is non-zero only on usage errors — gate your pipeline on the JSON summary.

Install (optional)

npm i -g dotenv-exposure-check
dotenv-exposure-check --url https://app.example.com

Zero dependencies. Read-only and keyless — every request goes straight from the tool to the target you name; nothing is stored, modified, or sent anywhere else. Only scan systems you own or are authorized to test.

Sister tools

Same active-probe philosophy across the stack, all MIT:

supabase-security · pocketbase-security · firebase-security · appwrite-security · nhost-security · strapi-security · directus-security · aws-s3-security · stripe-webhook-security · github-actions-security · web-exposure-mcp

License

MIT © Renzo Madueno

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