Description
During the scan, Kayran managed to find that an external, malicious files could be loaded.
That, might lead to Remote File Inclusion (RFI) attacks. The purpose of an RFI attack is stealing information from affected servers and taking over the site that allows content to be changed.
The attacker’s main purpose is to exploit the vulnerable mechanism found in the web application. He abuses it to upload malicious files from a remote URL located in another origin. (for example : backdoor shells)
This is an example of a PHP code that holds an RFI vulnerability. The following source code display what is occurring “behind the scenes” when a programmer writing a code holding RFI vulnerability :
<?php$page = $_POST['page'];
include($page);
?>
Recommendation
To prevent this vulnerability from occurring in the future, the user input must be verified and filtered correctly. Additionally, if the server is on Apache, make sure that allow_url_include is off so that it will not be possible to load content from any external URLs.
References
https://www.imperva.com/learn/application-security/rfi-remote-file-inclusion/
