W32.Kamil

When W32.Kamil runs, it does the following:

It creates these files:

• C:\Melhacker.vbs. (This file creates the Melhacker.zip file. It is detected by Symantec antivirus products.)
• C:\Nur_Mohd_Kamil.bat. (This file performs several actions. Details are described later in this document. It is detected by Symantec antivirus products.)
• C:\Windows\Nmksys32.vxd. (This is a text file. It is not malicious, and therefore, is not detected by Symantec antivirus products.)
• C:\Windows\Nmk.htm. (This is an .htm file that displays messages. It is not malicious, and therefore, is not detected by Symantec antivirus products.)
• C:\Nur_Mohd_Kamil.reg. (This file contains the Trojan's registry values and keys that are executed to modify the registry. It is not malicious, and therefore, is not detected by Symantec antivirus products.)
• Melhacker.zip. (This .zip file contains a DOS executable which is corrupted. The file name is Nmk.exe. It is not malicious, and therefore, is not detected by Symantec antivirus products.)

Next, the Trojan adds the value

RunIt         c:\windows\Nur_Mohd_Kamil.bat

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

This executes Nur_Mohd_Kamil.bat each time that you restart Windows.

Details about Nur_Mohd_Kamil.bat
If Nur_Mohd_Kamil.bat is executed, it does the following:

• It displays the message Loading Nur_Mohammad_Kamil...Please wait...
• It creates the C:\Nur_Mohd_Kamil folder.
• It moves C:\Windows\Desktop\*.* to C:\Nur_Mohd_Kamil.
• It moves C:\Windows\*.* to C:\Nur_Mohd_Kamil.
• It moves C:\mydocu~1\*.* to c:\Nur_Mohd_Kamil
• It copies C:\Nur_Mohd_Kamil.bat to C:\Windows\Startm~1\Progra~1\Startu~1\NMKLoad.bat.
• It copies C:\Nur_Mohd_Kamil.bat to C:\Windows.
• It renames C:\Progra~1\Norton~1\Fileter.dat to Nmk.sys
• It displays the message Nur_Mohammad_Kamil successfully update...Done

W32.Kamil also attempts to change the Internet Explorer home page download a file at http:/ /melhacker.netfirms.com/. If you go to that Web page, the Trojan attempts to download the Setupmvm.exe file. This file is a worm and is detected as W32.BleBla.J.Worm.

W32.Kamil has a Flash icon, which is used in an attempt to fool you into thinking that it is a Flash movie.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.

Summary