clsas32.exe is a Trojan W32.Rbot-AZO. clsas32.exe opens a back door on IRC channels. clsas32.exe spreads via open network shares. Related files: %System%\clsas32.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill clsas32.exe process and remove clsas32.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.