1. Web Security Academy
  2. Request smuggling
  3. Advanced
  4. Response queue poisoning
  5. Lab

Lab: Response queue poisoning via H2.TE request smuggling

PRACTITIONER

This lab is vulnerable to request smuggling because the front-end server downgrades HTTP/2 requests even if they have an ambiguous length.

To solve the lab, delete the user carlos by using response queue poisoning to break into the admin panel at /admin. An admin user will log in approximately every 15 seconds.

The connection to the back-end is reset every 10 requests, so don't worry if you get it into a bad state - just send a few normal requests to get a fresh connection.

Note

This lab supports HTTP/2 but doesn't advertise this via ALPN. To send HTTP/2 requests using Burp Repeater, you need to enable the Allow HTTP/2 ALPN override option and manually change the protocol to HTTP/2 using the Inspector.

Please note that this feature is only available from Burp Suite Professional / Community 2021.9.1.

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