W32/Sdbot-XK

Please follow the instructions for removing worms.

W32/Sdbot-XK is a network worm with backdoor functionality for the Windows platform.

W32/Sdbot-XK is capable of spreading to computers on the local network protected by weak passwords after receiving the appropriate backdoor command.

W32/Sdbot-XK will also attempt to spread by exploiting the following vulnerabilities:

RPC DCOM (MS03-026, MS03-039, MS04-012)
LSASS (MS04-011)
WorKStation service (MS03-049)
Microsoft SQL Server 2000 (pre service pack 3) (CAN-2002-0649)
Microsoft SQL servers with weak passwords

When first run, W32/Sdbot-XK moves itself to the Windows system folder as B.EXE. In order to run automatically each time a user logs in, W32/Sdbot-XK will set the following registry entries:

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
b.exe
b.exe

HKCU\Software\Microsoft\Windows\CurrentVersion\RunServices
b.exe
b.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
b.exe
b.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
b.exe
b.exe

W32/Sdbot-XK will attempt to stealth itself by dropping and running a file named MSDIRECTX.SYS. This file runs as a service named "msdirectx" and is detected as Troj/NtRootK-F. The following registry branch will be created:

HKLM\SYSTEM\CurrentControlSet\Services\msdirectx

W32/Sdbot-XK runs continuously in the background, providing backdoor access to the infected computer over IRC channels.

W32/Sdbot-XK will modify the following registry entries in order to disable DCOM and close restrictions on IPC$ shares:

HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
restrictanonymous
1

W32/Sdbot-XK will also set the following registry entries:

HKCU\SYSTEM\CurrentControlSet\Control\Lsa
b.exe
b.exe

HKCU\Software\Microsoft\OLE
b.exe
b.exe

W32/Sdbot-XK will attempt to disable the Windows Internet Connection Firewall, Automatic Updates and Security Center by modifying the following registry entries:

HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Start

HKLM\SYSTEM\CurrentControlSet\Services\wuauserv\Start

HKLM\SYSTEM\CurrentControlSet\Services\wscsv\Start

W32/Sdbot-XK can add and delete network shares and users on the infected computer.

W32/Sdbot-XK may modify the HOSTS file found in the <Windows system folder>\driver\etc folder in order to deny access to certain anti-virus websites. For example,

127.0.0.1 www.sophos.com
127.0.0.1 sophos.com

W32/Sdbot-XK will attempt to terminate a large number of security and anti-virus related processes.