hunt-spa-api

⚠️ AUTHORIZED USE ONLY This skill is for educational purposes or authorized security assessments only. You must have explicit, written permission from the system owner before using this tool. Misuse of this tool is illegal and strictly prohibited.

Mandatory confirmation gate Before running any command that probes, exploits, changes, persists on, extracts data from, or attempts credential access against a target:

1. Ask the user to state the exact target URL, IP, account, or resource.
2. Ask the user to confirm written authorization and the permitted scope.
3. Show the exact command(s) and explain their expected effect.
4. Wait for explicit confirmation in the current conversation.

Without that confirmation, remain read-only and provide defensive guidance only. Prefer a sandbox, disposable VM, or controlled lab.

When to use this skill

Trigger when:

• A target host returns a tiny HTML shell + big /static/js/*.js or /_next/static/* bundles (React/Vue/Angular/Next/Svelte SPA)
• You see a subdomain named console, app, dashboard, portal, admin, panel, manage, internal
• Recon surfaces any *api*, *-api*, api.* host
• A login page is OAuth/SSO-gated (the frontend auth tells you nothing about whether the API enforces auth)

The core insight: a SPA is a client to a backend API, and it ships the full map of that API — hosts, routes, sometimes keys — to anyone who views source. The login page being protected says nothing about whether the API behind it checks tokens. Auth is frequently enforced on the gateway/login and missing on a route group of the API.

DO NOT skip this because "the app needs login" — that's exactly when this pays off.

The play (5 steps)

1. Pull the shell + enumerate the bundles

curl -s https://console.target.com/ -o index.html
# React/CRA:
grep -oE '/static/js/[^"]+\.js' index.html
# Next.js:
grep -oE '/_next/static/[^"]+\.js' index.html
# generic:
grep -oiE 'src="[^"]+\.js[^"]*"' index.html

Download every bundle (they can be multi-MB — that's fine, it's all route data):

mkdir bundles
for j in $(grep -oE '/static/js/[^"]+\.js' index.html | sort -u); do
  curl -s "https://console.target.com$j" -o "bundles/$(echo "$j"|tr '/' '_')"
done

2. Harvest API hosts, routes, and secrets from the bundles

B=bundles/*.js
# Backend API hosts (incl. dev/beta/staging variants — often weaker auth)
grep -ohiE 'https://[a-z0-9.-]*(api|console|backend|service)[a-z0-9.-]*\.target\.com[a-z0-9/_-]*' $B | sort -u
# Versioned API base paths
grep -ohiE '/api/v[0-9]+/?' $B | sort -u
# Route literals — minified bundles store routes as STRING segments, not full URLs.
# Grep for quoted "resource/action" strings:
grep -ohiE '"[a-z0-9_-]+/[a-z0-9_/-]+"' $B | tr -d '"' \
  | grep -iE '(login|user|account|order|billing|invoice|payment|deal|report|token|otp|password|reset|admin|profile|auth|upload|export|role|permission|dashboard|wallet|finance|sales)' | sort -u
# Secrets (validate before trusting — most AIza keys are Maps/analytics, not Auth)
grep -ohiE '(AIza[0-9A-Za-z_-]{35}|AKIA[0-9A-Z]{16}|sk_live_[0-9A-Za-z]+|eyJ[A-Za-z0-9_-]{10,}\.[A-Za-z0-9_-]{10,}|apiKey["'"'"']?\s*[:=]\s*["'"'"'][^"'"'"']+)' $B | sort -u

Note: minifiers store routes as concatenated string segments (e.g. "account/payment/list"), NOT full /api/v2/... URLs — so a naive /api/v* grep returns nothing. Grep for the resource-word route strings and prepend the base yourself.

Lazy-loaded (async) chunks — don't stop at HTML-referenced bundles. CRA/webpack SPAs reference only runtime+main+vendor in index.html; numbered async route chunks are named inside main.js's chunk map and loaded at runtime, so grepping only /static/js/*.js from the shell truncates route coverage to eager chunks.

grep -oE '[0-9]+:"[a-f0-9]+"' bundles/*main*.js        # {chunkId:"hash"} pairs
# reconstruct /static/js/<id>.<hash>.chunk.js, download each, re-run route/host/secret harvest
# asset-manifest.json (if present) lists them all -> hunt-source-leak

3. Establish a CONTROL — find an endpoint that IS gated

Before declaring anything vulnerable, send an unauthenticated request to an endpoint you expect to be protected, and capture what correct rejection looks like:

curl -s -X POST https://api.target.com/api/users -H 'Content-Type: application/json' -d '{}'
# secure → {"error":"Missing or invalid authorization header"} or HTTP 401

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