# Hunt Host Header

Hunt Host Header Injection, password reset poisoning → ATO, web cache poisoning via...

- Repository: https://github.com/elementalsouls/Claude-BugHunter (5368 stars)
- Category: Writing
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add elementalsouls/Claude-BugHunter --skill hunt-host-header -g -a claude-code -y`
Codex: `npx skills add elementalsouls/Claude-BugHunter --skill hunt-host-header -g -a codex -y`
Cursor: `npx skills add elementalsouls/Claude-BugHunter --skill hunt-host-header -g -a cursor -y`
Gemini CLI: `npx skills add elementalsouls/Claude-BugHunter --skill hunt-host-header -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add elementalsouls/Claude-BugHunter`

## Description

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 the classic password-reset-poisoning class). Use on any forgot-password flow, CDN/reverse-proxy-fronted app, OAuth/OIDC endpoint, or absolute-URL-in-email feature.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# 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
on a fresh key, OOB hit from your Collaborator). Do **not** copy a CVE or H1 ID you have not
verified, a missing citation is always better than a wrong one.

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## Crown Jewel Targets

Host header injection that reaches password reset links = Critical (ATO for any user).

The rest: https://github.com/elementalsouls/Claude-BugHunter/blob/HEAD/skills/hunt-host-header/SKILL.md