codll.exe is a Trojan.Gravebot-A. codll.exe opens a back door on IRC channels. Related files: %System%\codll.exe %System%\sum.tgz More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill codll.exe process and remove codll.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.