W32/Tilebot-CW

Please follow the instructions for removing worms.

W32/Tilebot-CW is a worm and IRC backdoor Trojan for the Windows platform.

W32/Tilebot-CW spreads to other network computers by exploiting common buffer overflow vulnerabilites, including:

LSASS (MS04-011)
RPC-DCOM (MS04-012)
PNP (MS05-039)
ASN.1 (MS04-007)

W32/Tilebot-CW runs continuously in the background, providing a backdoor server which allows a remote intruder to gain access and control over the computer via IRC channels.

W32/Tilebot-CW includes functionality to access the internet and communicate with a remote server via HTTP.

When first run W32/Tilebot-CW copies itself to <Windows>\win32ssr.exe.

The file win32ssr.exe is registered as a new system driver service named "win32ssr", with a display name of "ImagePath" and a startup type of automatic, so that it is started automatically during system startup. Registry entries are created under:

HKLM\SYSTEM\CurrentControlSet\Services\Win32Sr

W32/Tilebot-CW sets the following registry entries, disabling the automatic startup of other software:

HKLM\SYSTEM\CurrentControlSet\Services\Messenger
Start
4

HKLM\SYSTEM\CurrentControlSet\Services\RemoteRegistry
Start
4

HKLM\SYSTEM\CurrentControlSet\Services\TlntSvr
Start
4

Registry entries are set as follows:

HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
restrictanonymous
1

HKLM\SOFTWARE\Microsoft\Security Center
UpdatesDisableNotify
1

HKLM\SOFTWARE\Microsoft\Security Center
AntiVirusDisableNotify
1

HKLM\SOFTWARE\Microsoft\Security Center
FirewallDisableNotify
1

HKLM\SOFTWARE\Microsoft\Security Center
AntiVirusOverride
1

HKLM\SOFTWARE\Microsoft\Security Center
FirewallOverride
1