An issue was discovered in MyBiz MyProcureNet 5.0.0. A malicious file can be uploaded to the webserver by an attacker. It is possible for an attacker to upload a script to issue operating system commands. This vulnerability occurs because an attacker is able to adjust the "HiddenFieldControlCustomWhiteListedExtensions" parameter and add arbitrary extensions to the whitelist during the upload. For instance, if the extension .asp is added to the "HiddenFieldControlCustomWhiteListedExtensions" parameter, the server accepts "secctest.asp" as a legitimate file. Hence malicious files can be uploaded in order to execute arbitrary commands to take over the server.
