lsasser.exe is a worm W32.Rbot-ATS. lsasser.exe opens a back door. lsasser.exe spreads via open network shares. Related files: %System%\lsasser.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill lsasser.exe process and remove lsasser.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.