ivhost.exe is a network worm W32.Rbot-BJN. ivhost.exe opens a back door on IRC channels. ivhost.exe spreads via the RPC-DCOM (MS04-012) and LSASS (MS04-011) buffer overflow vulnerabilities. Related files: %System%\ivhost.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill ivhost.exe process and remove ivhost.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.