Wsem.dll is a library file that contains malicious code, which implements main parasite functions. This file usually needs to be loaded by executables or other pest files. However, some threats inject Wsem.dll in the system, so it works as an independent component, for example, as a harmful web browser plugin or hidden system service.
The Wsem.dll file is installed and used by dialer DyFuCa.
In most cases Wsem.dll is responsible for all the harmful actions the pest takes. Removing this file will immediately terminate the parasite or partially disable it. That is why the Wsem.dll file must be manually deleted. If you cannot erase it, consider using recommended spyware removers, which will get rid of Wsem.dll and associated parasites for you.
Sometimes a presence of Wsem.dll does not indicate that your computer is infected. It can be an essential system file or a file installed by harmless legitimate software and therefore may not pose any threat to your privacy and the system. Although such cases are quite rare, you should thoroughly examine Wsem.dll before completely deleting or leaving it in the system.