hunt-host-header SKILL.md skillA
hunt-host-header from novaestellar/novahaku is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add novaestellar/novahaku/hunt-host-header@git:20260910.546fe86Pins git:20260910.546fe86 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- novaestellar/novahaku
- Path
testing/hunt/hunt-host-header/SKILL.md- Versions recorded
- 3
- Latest version
- git:20260910.546fe86, committed Sep 10, 2026
- First version recorded
- Sep 3, 2026
- Size
- 14,118 bytes
- Repository stars
- 28
- License
- MIT
Hunt Host Header Injection — password reset poisoning → ATO, web cache poisoning via unkeyed Host/X-Forwarded-Host, routing-based SSRF (Host picks upstream → cloud metadata/internal services), path-override SSRF/ACL-bypass (X-Original-URL/X-Rewrite-URL), OAuth redirect_uri/issuer poisoning, and absolute-URL link poisoning in emails. High to Critical when it reaches ATO or mass cache poisoning. Built on public Host-header research (PortSwigger 'Practical web cache poisoning' + James Kettle, and…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# HUNT-HOST-HEADER — Host Header Injection ## Grounding / Provenance This skill is built from the public Host-header attack literature, not invented payloads. Cite the *technique source* in your report, never a fabricated ID: - **Password-reset poisoning class** — the canonical write-up is Skelet's/Detectify-era "Practical HTTP Host header attacks" (the Django `request.get_host()` → password-reset-link case). Many frameworks built the reset URL from the request Host with no `ALLOWED_HOSTS`-style allowlist. Cite the framework + the reflected-Host behaviour you actually observed. - **Web cache poisoning via unkeyed Host / X-Forwarded-Host** — PortSwigger Research, James Kettle, "Practical Web Cache Poisoning" (2018) and "Web Cache Entanglement" (2020). These define unkeyed-input poisoning, which is the mechanism behind X-Forwarded-Host poisoning. - **Routing-based SSRF** — PortSwigger Research, "Cracking the lens" / routing-based SSRF (Host header steers the front-end's upstream selection). When you write the report, name the exact behaviour you reproduced (reflected header, cache HIT …
Read the whole file at its exact version.
How to install
mdr add novaestellar/novahaku/hunt-host-header@sha256:64ae269807ac41fdThe line at the top of this page pins the label git:20260910.546fe86, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_mtzt7nbuyou3v25o)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Sep 3, 2026 and Sep 10, 2026, about one every 3 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260910.546fe86 latest | 2026-09-10 | 546fe86 | 14,118 B | A | view · diff |
| git:20260903.29924dd | 2026-09-03 | 29924dd | 14,130 B | A | view · diff |
| git:20260903.fa855c4 | 2026-09-03 | fa855c4 | 14,101 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (14118 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
novaestellar/novahaku · 28 stars · license MIT · pushed 2026-09-28 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_mtzt7nbuyou3v25o GET https://markdownregistry.com/api/v1/resolve?ref=novaestellar/novahaku/hunt-host-header GET https://markdownregistry.com/api/v1/blob/64ae269807ac41fdef82679f080700f4d57f4b93bd1d29f43a601ec5febaa9de
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.