The MOVEitISAPI service in Ipswitch MOVEit DMZ before 8.2 provides different error messages depending on whether a FileID exists, which allows remote authenticated users to enumerate FileIDs via the X-siLock-FileID parameter in a download action to MOVEitISAPI/MOVEitISAPI.dll.
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.