hunt-business-logic
hunt-business-logic is a Claude Code skill that detects e-commerce and SaaS vulnerabilities including coupon stacking, negative quantity price manipulation, client-side checkout trust, mass-assignment price overrides, and race condition cart swaps. Use this skill when testing payment platforms, marketplaces, subscription systems, and tiered-access applications where financial transactions or access controls can be bypassed through business logic flaws.
git clone --depth 1 https://github.com/elementalsouls/Claude-BugHunter /tmp/hunt-business-logic && cp -r /tmp/hunt-business-logic/skills/hunt-business-logic ~/.claude/skills/hunt-business-logicSKILL.md
## Crown Jewel Targets
Business logic vulnerabilities pay highest in platforms where financial transactions, identity verification, and access controls intersect with real-world consequences. The richest targets are:
- **E-commerce & payment platforms** (Valve/Steam, Shopify) — payment flow manipulation, free goods, price tampering
- **Marketplace & gig economy apps** (Airbnb, Uber) — identity/verification bypass enabling fraud or unsafe interactions
- **SaaS with tiered access** (Mozilla Monitor) — bypassing verification to unlock monitoring features without entitlement
- **High-traffic consumer apps** (Snapchat, Yelp) — rate-limit bypass enabling spam, enumeration, or abuse at scale
Asset types that pay: checkout flows, subscription endpoints, callback/verification systems, webhook handlers, employee/internal portals exposed to the internet, and any endpoint that trusts client-supplied data to make authorization decisions.
---
## Attack Surface Signals
**URL patterns to watch:**
- `/checkout`, `/order`, `/subscribe`, `/payment`, `/verify`, `/confirm`, `/callback`
- `/internal`, `/employee`, `/summit`, `/staff`, `/admin` — internal pages accidentally public
- `/api/v*/payment`, `/api/v*/notify`, `/webhook` — payment provider callbacks
- Endpoints accepting `X-Forwarded-For`, `X-Real-IP`, `CF-Connecting-IP` headers
**Response/header signals:**
- `Set-Cookie` with unvalidated session state tied to cart or order data
- Payment provider names in responses: `Smart2Pay`, `Stripe`, `PayPal`, `Braintree`
- Redirect chains through third-party payment pages (in-flight data opportunity)
- `200 OK` on subscription/verification endpoints with no CAPTCHA or token
**JS patterns:**
- Hardcoded internal URLs in frontend bundles (`/employee/`, `/staff/`, `/internal/`)
- Client-side price calculation before server submission
- Verification logic that only checks on the frontend (`if (verified) { ... }`)
- `fetch('/api/subscribe', { method: 'POST', body: ... })` with no anti-CSRF token or rate-limit token
**Tech stack signals:**
- Shopify storefronts with draft/unpublished channel pages
- Apps using IP-based rate limiting without session/account binding
- Payment webhooks with no HMAC signature validation
- SMS/phone callback flows that don't verify ownership before enabling features
---
## Step-by-Step Hunting Methodology
1. **Map all authentication boundaries.** Spider the target. Identify pages/endpoints that serve authenticated content (employee portals, premium features, order pages) and test each unauthenticated. Look for internal pages indexed in JS bundles or linked from robots.txt/sitemap.xml.
2. **Identify every verification flow.** Enumerate: email verification, phone/SMS verification, payment verification, CAPTCHA, age gates. For each, test: what happens if you skip the verification step entirely? What happens if you replay a valid token on a different account?
3. **Test rate-limiting controls on every form.** For every POST endpoint (subscribe, login, OTP, search), send 50+ rapid requests. Vary: remove cookies, rotate `X-Forwarded-For` / `X-Real-IP` headers, change `User-Agent`. Check if the server uses IP from headers rather than connection IP.
4. **Intercept and tamper with payment flows.** Use Burp Suite to intercept every request between your browser, the application, and the payment provider. Identify where price, currency, order ID, or status fields are set. Attempt to modify amounts to $0.01 or currency to a low-value currency. Look for POST-back/webhook endpoints that accept payment confirmation — test if they validate HMAC/signature.
5. **Test phone/callback number verification.** Whenever a platform accepts a callback number, test: can you set it to a number you don't own? Does the platform call/text that number and grant trust based solely on submission? Try setting it to a victim's number.
6. **Check for unprotected employee/internal surfaces.** Search Shodan, GitHub, JS bundles, and Wayback Machine for internal subdomain/path references. Test access without authentication. Check if these surfaces allow order placement, data access, or privilege escalation.
7. **Validate business impact.** For each finding, determine: does this result in financial loss, unauthorized access, or data exposure? Document the end-to-end chain.
---
## Payload & Detection Patterns
**Rate limit bypass via header rotation:**
```bash
# Rotate X-Forwarded-For to bypass IP rate limiting
for i in $(seq 1 100); do
curl -s -X POST https://target.com/api/subscribe \
-H "X-Forwarded-For: 10.0.0.$i" \
-H "X-Real-IP: 10.0.0.$i" \
-H "Content-Type: application/json" \
-d '{"email":"victim+'"$i"'@example.com"}' \
-o /dev/null -w "%{http_code}\n"
done
```
**Payment tampering — modify in-flight price:**
```http
POST /payment/initiate HTTP/1.1
Host: target.com
amount=0.01¤cy=USD&order_id=12345&product_id=99
```
```bash
# Look for unvalidated webhook endpoints
curl -X POST https://target.com/payment/callback \
-H "Content-Type: application/json" \
-d '{"status":"success","amount":"0.01","order_id":"12345","transaction_id":"fake-txn"}'
```
**Unauthenticated internal page discovery:**
```bash
# Check robots.txt and sitemap for internal paths
curl -s https://target.com/robots.txt | grep -iE "(disallow|allow)"
curl -s https://target.com/sitemap.xml | grep -iE "(employee|internal|staff|summit|admin)"
# Grep JS bundles for internal paths
curl -s https://target.com/assets/app.js | grep -oE '"/[a-zA-Z0-9/_-]{3,50}"' | sort -u
```
**Email verification bypass:**
```bash
# Skip the verification step: hit the post-verification API endpoint directly
# with an unverified session. If it succeeds, the gate is UI-only.
curl -s -X POST https://monitor.target.com/api/monitoring/enable \
-H "Cookie: session=<your_unverified_session>" \
-H "Content-Type: application/json" \
-d '{"email":"victim@example.com"}'
# Replay verification token on different account
curl -X POST https:/End-to-end Android APK red-team pipeline — automated APK acquisition (Play Store + apkpure + apkmirror fallback), jadx decompilation, secret/URL/JWT/Firebase grep, pinned-cert extraction, exported-component enumeration, Frida runtime instrumentation templates, intent-injection probes. Built from an authorized external red-team engagement where 7 APKs were pulled manually, 4 download attempts truncated, and a hardcoded JWT + 30 internal API endpoints were recovered from one of the apps. Use when target has a mobile app catalogue (Play Store developer page), when you find an APK URL hosted on a web server, or when post-recon mentions "mobile app" in scope.
Run autonomous hunt loop on a target — scope check → recon → rank surface → hunt → validate → report with configurable checkpoints. Usage: /autopilot target.com [--paranoid|--normal|--yolo]
Local-tooling companion to the bug-bounty orchestrator — carries the SAME complete bug-bounty workflow, but reach for THIS variant when you also need to resolve where tools, wordlists, and clones are installed on the local machine (jhaddix, SecLists, trufflehog, ffuf, dalfox, ghauri); for pure orchestration/routing use the bug-bounty skill. Workflow it covers — recon (subdomain enumeration, asset discovery, fingerprinting, HackerOne scope, source code audit), pre-hunt learning (disclosed reports, tech stack research, mind maps, threat modeling), vulnerability hunting (IDOR, SSRF, XSS, auth bypass, CSRF, race conditions, SQLi, XXE, file upload, business logic, GraphQL, HTTP smuggling, cache poisoning, OAuth, timing side-channels, OIDC, SSTI, subdomain takeover, cloud misconfig, ATO chains, agentic AI), LLM/AI security testing (chatbot IDOR, prompt injection, indirect injection, ASCII smuggling, exfil channels, RCE via code tools, system prompt extraction, ASI01-ASI10), A-to-B bug chaining (IDOR→auth bypass, SSRF→cloud metadata, XSS→ATO, open redirect→OAuth theft, S3→bundle→secret→OAuth), bypass tables (SSRF IP bypass, open redirect bypass, file upload bypass), language-specific grep (JS prototype pollution, Python pickle, PHP type juggling, Go template.HTML, Ruby YAML.load, Rust unwrap), and reporting (7-Question Gate, 4 validation gates, human-tone writing, templates by vuln class, CVSS 3.1, PoC generation, always-rejected list, conditional chain table, submission checklist). Use when you need the local install path of a tool / wordlist / clone for a hunt, or as the full-workflow variant when operating from this local toolkit; for general routing use the bug-bounty skill. 中文触发词：漏洞赏金、安全测试、渗透测试、漏洞挖掘、信息收集、子域名枚举、XSS测试、SQL注入、SSRF、安全审计、漏洞报告
Use at the START of any bug bounty hunting session, when switching targets, or when feeling lost about what to do next. Master orchestrator that combines the 5-phase non-linear hunting workflow with the critical thinking framework (developer psychology, anomaly detection, What-If experiments). Routes to all other skills based on current hunting phase. Also use when asking "what should I do next" or "where am I in the process.
Complete bug bounty workflow — recon (subdomain enumeration, asset discovery, fingerprinting, HackerOne scope, source code audit), pre-hunt learning (disclosed reports, tech stack research, mind maps, threat modeling), vulnerability hunting (IDOR, SSRF, XSS, auth bypass, CSRF, race conditions, SQLi, XXE, file upload, business logic, GraphQL, HTTP smuggling, cache poisoning, OAuth, timing side-channels, OIDC, SSTI, subdomain takeover, cloud misconfig, ATO chains, agentic AI), LLM/AI security testing (chatbot IDOR, prompt injection, indirect injection, ASCII smuggling, exfil channels, RCE via code tools, system prompt extraction, ASI01-ASI10), A-to-B bug chaining (IDOR→auth bypass, SSRF→cloud metadata, XSS→ATO, open redirect→OAuth theft, S3→bundle→secret→OAuth), bypass tables (SSRF IP bypass, open redirect bypass, file upload bypass), language-specific grep (JS prototype pollution, Python pickle, PHP type juggling, Go template.HTML, Ruby YAML.load, Rust unwrap), and reporting (7-Question Gate, 4 validation gates, human-tone writing, templates by vuln class, CVSS 3.1, PoC generation, always-rejected list, conditional chain table, submission checklist). Use for ANY bug bounty task — starting a new target, doing recon, hunting specific vulns, auditing source code, testing AI features, validating findings, or writing reports. 中文触发词：漏洞赏金、安全测试、渗透测试、漏洞挖掘、信息收集、子域名枚举、XSS测试、SQL注入、SSRF、安全审计、漏洞报告
Bugcrowd-specific reporting tactics complementing report-writing: VRT category search-and-fallback strategy when no exact match exists, manual severity override when VRT defaults underrate impact, severity-request paragraph as first body section, OOS-clause rebuttal templates (rate limiting on auth-flow endpoints, debug-info framing, user-enumeration with sensitive PII, theoretical-issue counter), chained-finding cross-reference patterns, target selection for QA-vs-prod programs, researcher-side hygiene (Bugcrowdninja email alias, account state restoration, friendly-tester posture). Use when filing a Bugcrowd submission, when VRT default seems wrong, when triager closes as OOS or downgrades severity, when chaining linked submissions, or when scope distinguishes production from QA. Pairs with report-writing and triage-validation.
Build an exploit chain — given bug A, finds B and C to combine for higher severity and payout. Knows common chain patterns: IDOR→ATO, SSRF→cloud metadata, XSS→ATO, open redirect→OAuth theft, S3→bundle→secret→OAuth. Usage: /chain
Cloud IAM red-team attack chain across AWS, Azure, GCP — focused on EXTERNAL exploitation paths and post-credential-discovery privilege analysis. Covers IAM enumeration (aws iam, az role, gcloud iam), STS/AssumeRole chaining, Azure Managed Identity abuse (via SSRF/leak), GCP service account JSON abuse, IMDSv1/v2 attacks via SSRF, K8s ServiceAccount token privilege analysis once held (token discovery / cluster exposure is owned by hunt-k8s), role-trust-policy confused-deputy, cross-account assume-role enumeration, IAM privilege escalation patterns (24+ AWS, 8+ Azure, 6+ GCP), and AWS Cognito Identity Pool unauthenticated-role attack chain (GetId → GetCredentialsForIdentity → IAM role abuse). Built for the case where recon yields a credential (key, JSON, token) and you need to know what it grants and how to escalate. Use when an AWS key / Azure secret / GCP service account JSON / K8s SA token surfaces from a code repo, JS bundle, APK, breach corpus, or SSRF chain.