Lab: Exploiting HTTP request smuggling to bypass front-end security controls, CL.TE vulnerability

Summary: This PortSwigger lab presents a front-end and back-end server setup where the front-end does not support chunked encoding, and an admin panel at /admin is blocked from the front end. The intended solution is a CL.TE request smuggling attack that smuggles a request to the back end to access the admin panel and delete the user carlos, using HTTP/1 techniques even though the lab supports HTTP/2.
What's compelling: The attack works precisely because the front-end and back-end servers disagree on how to parse request boundaries, so the front-end's block on /admin means nothing once a smuggled request reaches the back end. Any architecture where a proxy and origin parse requests differently inherits the same gap.

Read the original at PortSwigger Research ↗

Topics: Vulnerabilities & Patching
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