W32/Tilebot-CA

Please follow the instructions for removing worms.

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

W32/Tilebot-CA spreads to other network computers by exploiting common buffer overflow vulnerabilities, including: WKS (MS03-049) (CAN-2003-0812), PNP (MS05-039) and ASN.1 (MS04-007).

W32/Tilebot-CA 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.

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

The file Iass.exe is registered as a new system driver service named "lsass", with a display name of "Local Security Authority Subsystem Service" and a startup type of automatic, so that it is started automatically during system startup. Registry entries are created under:

HKLM\SYSTEM\CurrentControlSet\Services\lsass\

W32/Tilebot-CA 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\Policies\Microsoft\Windows\WindowsUpdate
DoNotAllowXPSP2
1

HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
restrictanonymous
1

Registry entries are created under:

HKLM\SOFTWARE\Microsoft\Security Center\
HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile\
HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile\