hosts.dll is a Backdoor.Zagaban. hosts.dll spreads via open network shares. Related files: %System%\gld.exe %System%\gld.dll %System%\hosts.dll %System%\socks.dll Adds the value: "Shell" = "explorer.exe %System%\gld.exe" to the Windows startup registry keys. More info: http://securityresponse.symantec.com/avc... Removal: Remove hosts.dll from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.