Lab: URL-based access control can be circumvented

Summary: PortSwigger's lab describes a site with an unauthenticated admin panel at /admin that a front-end system blocks from external access, while the back-end framework supports the X-Original-URL header. Sending a request to / with X-Original-URL: /invalid returns a not-found response, and changing the header to /admin reaches the admin page, after which /admin/delete with ?username=carlos in the query string deletes the user carlos.
Key Takeaway: The front-end block on /admin is defeated by a single header the back-end trusts, so any access control enforced only at the edge can be bypassed by a request that never touches the blocked path.

Read the original at PortSwigger Research ↗

Topics: Vulnerabilities & Patching
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