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Jon MarienStudy Desk

BSCPServer-side

Host header attacks

Outline only. The Host header is client-influenced, and some apps still use it to build links or pick a tenant.

8 min read · Academy topic: HTTP Host header attacks · Outline, not a finished note

Outline. This module is on the map so you can track it. The page below is a writing checklist, not finished study material.

Objectives

  • Explain why Host is not a trustworthy source of the site's own name
  • Connect password-reset links and caches to that mistake
On this page
  1. TODO
  2. Checklist

TODO

Write the concept. Leave lab syntax in the Academy exercise.

Checklist

  • The browser sends Host. A proxy may also see X-Forwarded-Host. Neither is proof of the name the application should call itself.
  • Password-reset and email links built from that header can point at a name the requester chose. The bug is the link builder.
  • Virtual hosting and multi-tenant routing that trust the header can select the wrong site. The defender’s fix is a configured canonical name, not the request’s copy of it.
  • Cache interaction belongs in the cache-poisoning outline.
  • Lab work stays on the lab host. Rewriting Host against a real tenant is out of scope.

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