W32/Zooty-A

Please follow the instructions for removing worms.

You will also need to edit the following registry entries, if present. Please read the warning about editing the registry.

At the taskbar, click Start|Run. Type 'Regedit' and press Return. The registry editor opens.

Before you edit the registry, you should make a backup. On the 'Registry' menu, click 'Export Registry File'. In the 'Export range' panel, click 'All', then save your registry as Backup.

Locate the HKEY_LOCAL_MACHINE entries:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run\
Windows Host Device = hostsvc.exe
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices\
Windows Host Device = hostsvc.exe

and delete them if they exist.

Locate the HKEY_LOCAL_MACHINE entry:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\
Shell = explorer.exe hostsvc.exe

it should contain a reference to explorer.exe (or possibly NALWIN32.exe if you are using NetWare) only. Remove any reference to any file you deleted. You may need to replace the reference to explorer.exe.

Each user has a registry area named HKEY_USERS\[code number indicating user]\. For each user locate the entry:

HKCU\[code number]\Software\Microsoft\Windows\CurrentVersion\Run\
Windows Host Device = hostsvc.exe

and delete it if it exists.

Close the registry editor.

• Replace the Hosts file from a backup or edit it in Notepad to remove the changes that the Trojan has made.
• Check your administrator passwords and review network security.

W32/Zooty-A is a backdoor Trojan and network worm which may change the file C:\<Windows system>\Drivers\etc\HOSTS file to prevent access to several anti-virus and security-related websites and copy itself into the Windows system folder as HOSTSVC.EXE.

The following registry entries will be set to ensure that this worm is executed automatically upon restart:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run\
Windows Host Device = hostsvc.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices\
Windows Host Device = hostsvc.exe

HKCU\Software\Microsoft\Windows\CurrentVersion\Run\
Windows Host Device = hostsvc.exe

W32/Zooty-A changes the following registry entry by appending the name of the worm to the existing entry:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\
Shell = explorer.exe hostsvc.exe