W32.Navidad.16896

1. Displays a dialog box with a "winking smiley face" (emoticon):
   
   ;)
   
   and the title:
   
   Error
   
2. If you are running Windows NT/2000, the worm adds the following registry key:
   
   HKEY_CURRENT_USER\Software\Emanuel
   
   This key was supposed to be used to see if the computer was already infected. However, because of bugs in the code, the registry key is not utilized.
   
3. Next, the worm does one of the following:
   • If you are running Windows 95/98, the worm modifies the following registry key:
     
     HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
     Windows\CurrentVersion\Run
     
     and adds the value
     
     Win32BaseServiceMOD        \Windows\System\Wintask.exe
     
   • If you are running Windows NT/2000, the worm modifies the following registry key:
     
     HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
     Windows\CurrentVersion\Run
     
     and adds the value
     
     Win32BaseServiceMOD       C:\Winnt\System32\Wintask.exe
     
     
4. The worm then copies itself into the \Windows\System folder as Wintask.exe.
5. After the file has been copied, the worm modifies an additional registry key.
   
   • If you are running Windows 95/98, the worm changes
     
     HKEY_LOCAL_MACHINE\SOFTWARE\CLASSES\
     exefile\shell\open\command
     
     to equal
     
     \Windows\System\wintask.exe "%1" %*"
     
   • If you are running Windows NT/2000, the worm changes
     
     HKEY_CLASSES_ROOT\exefile\
     shell\open\command
     
     to equal
     
     C:\Winnt\System32\Wintask.exe "%1" %*"
     
6. Next, the worm begins the email routine. The worm utilizes MAPI to send mail and works with Microsoft Outlook. The worm checks for all messages in your Inbox and replies to those messages that have one attachment. The reply consists of the same subject line and body, but contains the worm attached as Emanuel.exe.
7. Finally, the worm places a flower icon in the system tray of the taskbar. When the mouse pointer is over the icon, the worm displays a yellow dialog box with the message:
   
   Come on lets party!!!
   
   NOTE: Once the infection occurs, a new flower icon will appear in the system tray each time that you attempt to run an executable file.
   
8. When you click the icon, a dialog box with a button appears. The button contains the text
   
   Nunca presionar este boton
   
   (Translation: Never press this button)
   
   • If you click the button, an error box with the title
     
     Emmanuel.....
     
     displays the message
     
     Emmanuel-God is with us!May god bless u.And Ash, Lk and LJ!!!
     
   • If you close the dialog box by clicking the X instead of clicking the button, the following message appears:
     
     May GOd bless u;D
     
     NOTE: The ;D is a "winking big grin emoticon."
     
     The box then closes.

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.