W32/Sdbot-DFQ is a worm with backdoor functionality for the Windows platform.
W32/Sdbot-DFQ 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/Sdbot-DFQ includes functionality to access the internet and communicate with a remote server via HTTP.
When first run W32/Sdbot-DFQ copies itself to <Windows>\ntvdm.exe.
The file ntvdm.exe is registered as a new system driver service named "NTVDM.", with a display name of "NTVDM." and a startup type of automatic, so that it is started automatically during system startup. Registry entries are created under:
HKLM\SYSTEM\CurrentControlSet\Services\NTVDM.
The following registry entries are set, disabling system software:
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System
DisableTaskMgr
1
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System
DisableRegistryTools
1
W32/Sdbot-DFQ 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\Windows NT\CurrentVersion\Winlogon
SFCScan
0
HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile
EnableFirewall
0
HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile
EnableFirewall
0
HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
DoNotAllowXPSP2
1
HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
SFCDisable
ffffff9d
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Shell
Explorer.exe %WINDIR%\ntvdm.exe
Registry entries are created under:
HKLM\SOFTWARE\Microsoft\Security Center
HKLM\SOFTWARE\Symantec\LiveUpdate Admin