1. Web Security Academy
  2. HTTP Host header attacks
  3. Exploiting
  4. Lab

Lab: Host validation bypass via connection state attack


This lab is vulnerable to routing-based SSRF via the Host header. Although the front-end server may initially appear to perform robust validation of the Host header, it makes assumptions about all requests on a connection based on the first request it receives.

To solve the lab, exploit this behavior to access an internal admin panel located at, then delete the user carlos.

This lab is based on real-world vulnerabilities discovered by PortSwigger Research. For more details, check out Browser-Powered Desync Attacks: A New Frontier in HTTP Request Smuggling.

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