What is PUP.Winlogon.Heuristic? Experienced security professionals has determined that the PUP.Winlogon.Heuristic is a malicious software. It is dropped or downloaded on your personal computer while surfing the Internet. This security threat can perform a number of harmful actions of a developers’s choice on your PC system. The PUP.Winlogon.Heuristic may alter system settings and files, create