Ipswitch MOVEit DMZ before 8.2 provides different error messages for authentication attempts depending on whether the user account exists, which allows remote attackers to enumerate usernames via a series of SOAP requests to machine.aspx.
http://seclists.org/fulldisclosure/2016/Jan/95
http://docs.ipswitch.com/MOVEit/DMZ82/ReleaseNotes/MOVEitReleaseNotes82.pdf