hunt-http-smuggling
Hunt HTTP Request Smuggling detects and exploits request parsing discrepancies between front-end proxies and back-end servers, particularly CL.TE, TE.CL, H2.CL, and H2.TE variants where headers like Content-Length and Transfer-Encoding are interpreted inconsistently. Use this skill when targeting HTTP/1.1 and HTTP/2 infrastructure in bug bounty programs, especially legacy or custom proxy deployments that lack RFC 9112 enforcement, to achieve cache poisoning, credential theft, and authentication bypass.
git clone --depth 1 https://github.com/elementalsouls/Claude-BugHunter /tmp/hunt-http-smuggling && cp -r /tmp/hunt-http-smuggling/skills/hunt-http-smuggling ~/.claude/skills/hunt-http-smugglingSKILL.md
## 17. HTTP REQUEST SMUGGLING > Lowest dup rate. $5K–$30K. PortSwigger research by James Kettle. ### CL.TE (Content-Length front, Transfer-Encoding back) ```http POST / HTTP/1.1 Content-Length: 13 Transfer-Encoding: chunked 0 SMUGGLED ``` ### Detection ``` 1. Burp extension: HTTP Request Smuggler 2. Right-click request → Extensions → HTTP Request Smuggler → Smuggle probe 3. Manual timing: CL.TE probe + ~10s delay = backend waiting for rest of body ``` ### Impact Chain ``` Poison next request → access admin as victim Steal credentials → capture victim's session Cache poisoning → stored XSS at scale ``` --- ## Target-Suitability Matrix (2026 reality check) The classic CL.TE / TE.CL payloads are NOT universally exploitable in 2026. Modern proxies are RFC 9112 strict by default. Fingerprint the front-end BEFORE investing time. | Front-end | CL.TE | TE.CL | H2.CL | H2.TE | Notes | |---|---|---|---|---|---| | **Nginx ≥ 1.21** | NO | NO | partial (H2 ingress) | partial | RFC-strict; rejects CL+TE with HTTP 400. Verified locally on Nginx 1.27 — all 9 documented variants killed by front-end ([docs/verification/phase2h-smuggling-cachepoison.md](../../docs/verification/phase2h-smuggling-cachepoison.md)). | | **Caddy 2.x** | NO | NO | — | — | Hardened by default | | **Envoy ≥ 1.20** | NO | NO | partial | partial | Hardened in most paths | | **HAProxy ≤ 2.4** | ✓ | ✓ | — | — | **Vulnerable**, see CVE-2021-40346 | | **AWS ALB + specific upstream** | partial | partial | ✓ | ✓ | Several disclosed-paid reports 2022-2024 | | **Cloudflare → S3 / Lambda chains** | — | — | ✓ | ✓ | H2-downgrade attacks remain viable | | **Older F5 BIG-IP (TMM < 16)** | ✓ | — | — | — | Vendor advisories | | **Citrix ADC / NetScaler (older firmware)** | ✓ | ✓ | — | — | Disclosed in 2020-2022 | | **Squid 3.x** | ✓ | — | — | — | Older deployments | | **Apache Traffic Server (older)** | ✓ | ✓ | ✓ | ✓ | PortSwigger research | | **Apache mod_proxy_ajp → Tomcat** | — | — | — | — | Cross-protocol HTTP→AJP desync (CVE-2022-26377); smuggled request is opaque to the WAF and reaches internal AJP admin/status paths that lack the external auth controls | | **Custom Python / Go proxies** | ✓ | ✓ | — | — | Frequently miss RFC enforcement | ### Operator fingerprint quick-check ```bash curl -sI https://target/ | grep -i "Server:" ``` - `nginx/1.21+`, `Caddy`, `envoy` → CL/TE classic is dead — pivot to H2.CL/H2.TE if the front-end speaks HTTP/2, or look for legacy proxies upstream - `HAProxy`, header points to AWS/CDN → run the full payload matrix - No Server header → assume hardened, but run a single quick `space-before-colon` probe; if it doesn't 400, dig deeper ### H2.CL / H2.TE (the modern dominant vector) H2-downgrade smuggling attacks rely on the front-end speaking HTTP/2 to the client and HTTP/1.1 to origin. The downgrade introduces CL/TE confusion because HTTP/2's frame-length headers don't survive the conversion cleanly. Most CDN+origin chains in 2024-2026 use this exact topology. Tools that send HTTP/2 raw frames (Burp Pro's HTTP Request Smuggler extension, `h2csmuggler`, `smuggler.py`) are the right starting point against CDN-fronted targets. Avoid HTTP/1.1-only test clients (curl, raw sockets) against H2-front-ended targets — you'll send the wrong protocol entirely. ### Mass credential harvesting — the "collector gadget" The highest-impact smuggling outcome needs no per-victim interaction. Instead of blindly poisoning the queue, smuggle a request aimed at a **back-end handler that echoes the full request** — a search endpoint that reflects headers, or a redirect that mirrors the request line. The next victim's headers (`Cookie`, `Authorization`, `X-Access-Token`) get attributed to your smuggled request, and the reflecting handler returns them **in a response you read**. Repeated on a busy keep-alive socket, this harvests live credentials from arbitrary users at scale — and it works even through a CDN (Akamai/Cloudflare) when the CDN↔origin hop desyncs. Chains to `hunt-ato`. --- ## Related Skills & Chains - **`hunt-cache-poison`** — Smuggling + cache is the canonical critical chain; one smuggled request becomes the cached response for every subsequent victim. Chain primitive: CL.TE smuggle a request whose response body contains attacker HTML/JS → front-end cache stores it under a popular URL (`/`, `/login`) → de-sync poisoning where the smuggled request becomes the cached response for the next N victims, persisting for the cache TTL. - **`hunt-auth-bypass`** — Smuggling reaches internal-only routes that the front-end WAF/auth-proxy filters out. Chain primitive: smuggle `GET /admin/users HTTP/1.1` past the front-end ACL that blocks external `/admin/*` → backend processes the smuggled request as if from a trusted internal source → bypass front-end auth by smuggling internal-routed request → admin data in the response queue. - **`hunt-idor`** — Smuggling attaches the NEXT user's session cookies to an attacker-controlled request path. Chain primitive: smuggle `GET /api/me HTTP/1.1` with no cookies → backend pairs it with the next legitimate user's incoming connection cookies → victim's session cookie attached to attacker's smuggled request → attacker reads the response containing victim's PII/tokens. - **`hunt-xss`** — Smuggling injects XSS payloads into the response stream of the next victim without ever appearing in a URL parameter. Chain primitive: smuggled request body contains reflected payload that the backend renders into the next response in the queue → next visitor to `/` receives attacker HTML inline → reflected XSS at every visitor without any URL parameter visible to them or to logs. - **`security-arsenal`** — Reach for the smuggling payload bank (CL.TE / TE.CL / TE.TE obfuscations, H2.CL downgrade probes, h2csmuggler one-liners, Burp HTTP Request Smuggler extension config) and the time-delay confirmation template before manual hex-editing. - **`triage-validation`** — Run the Pre-Severity Gate before claimi
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.