W32.HLLW.Henpeck

When this worm is executed, it does the following:

First, it displays a small window that has two buttons: Generate and Quit. If you click Generate, a key is displayed in the window. This appears to be an attempt to disguise itself as a CD key generator.

Next, the worm sends the following message to all contacts in the MSN Messenger for Windows contact list:

Hey!! Could you please check this program for me? :)  I made it myself and want people to test it. Its a readme with the program that explains what it does! <removed link> <- There you can download it! give me advices on what to upgrade please!!

NOTE: The link no longer works. Currently, if you click the link, a page appears with the message that says that you are not authorized to view the Web page.

Next, the worm attempts to download two additional files from a Web site. If it is successful, the files are saved as C:\Update35784.exe and C:\Hehe2397824.exe. Norton AntiVirus detects these two Trojans as W32.IRCBot.Gen. However, at the time that this document was written, it was no longer possible to download the two files.

If C:\Hehe2397824.exe is executed it does the following:

• It copies itself as the file %windir%\WinUpdat.exeupdate.ur.address.
• It creates the value
  
  WinUpdat %windir%\WinUpdat.exeupdate.ur.address
  
  in the registry key
  
  HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  
  so that it is executed each time that you start Windows.

Finally, the worm tries to find what appears to be CD keys that belong to the game named Half-Life and to an add-on for the game named Counterstrike. The worm looks for them in these locations:

HKEY_CURRENT_USER\Software\Valve\Half-Life\Settings\Key
HKEY_CURRENT_USER\Software\Valve\CounterStrike\Settings\Key

If the worm finds the keys, it includes them in an MSN message that it sends to the hacker.

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