W32/Forbot-EW

Please follow the instructions for removing worms.

Change any data that may have become compromised.

You will also need to edit the following registry entries, if they are 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\
HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce\
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices\

and remove any reference to any file you deleted.

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

HKU\[code number]\Software\Microsoft\Windows\
CurrentVersion\Run\

HKU\[code number]\Software\Microsoft\Windows\
CurrentVersion\RunOnce\

and remove any reference to any file you deleted.

Close the registry editor.

W32/Forbot-EW is a network worm with backdoor functionality for the Windows platform.

When first run, W32/Forbot-EW copies itself to the Windows system folder as kav32.exe and sets the following registry entries in order to run each time a user logs on:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
NvCplScan
kav32.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce
NvCplScan
kav32.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
NvCplScan
kav32.exe

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
NvCplScan
kav32.exe

HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce
NvCplScan
kav32.exe

W32/Forbot-EW also creates its own service named NvCplScan, with the display name NvCplScan.

Once installed, W32/Forbot-EW connects to a preconfigured IRC server and joins a channel from which an attacker can issue further commands. These commands can cause the infected machine to perform any of the following actions:

flood a remote host (by either ping or HTTP)
start a SOCKS4 proxy server
start an HTTP server
start an FTP server
portscan randomly-chosen IP addresses
execute arbitrary commands
steal information such as passwords and product keys
upload/download files

The worm can spread to unpatched machines affected by the LSASS vulnerability and through backdoors left open by the Troj/Optix Trojans.

The following patches for the operating system vulnerabilities exploited by W32/Forbot-EW can be obtained from the Microsoft website:

MS04-011