> A reverse proxy is a server that sits between clients and backend servers, forwarding client requests to the appropriate server while hiding the backend infrastructure and often providing load balancing or caching. Misconfigurations in a reverse proxy, such as improper access controls, lack of input sanitization in proxy_pass directives, or trusting client-provided headers like X-Forwarded-For, can lead to vulnerabilities like unauthorized access, directory traversal, or exposure of internal resources.
Source: Reverse Proxy Misconfigurations/README.md in PayloadsAllTheThings. From PayloadsAllTheThings by Swissky and contributors. MIT License, Copyright (c) 2019 Swissky.