source: https://www.securityfocus.com/bid/22093/info

The AVM Fritz!DSL IGD Control Service is prone to a remote information-disclosure vulnerability because the application fails to properly sanitize user-supplied input.

Exploiting this issue allows remote, unauthenticated attackers to retrieve the contents of arbitrary files from vulnerable computers with SYSTEM-level privileges. Information harvested may aid in further attacks.

http://www.example.com:49001/..%5C..%5C..%5Cwindows%5Csystem.ini