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Discovered: November 29, 2000
Updated: February 13, 2007 11:59:59 AM
Also Known As: Navidad.E
Type: Worm

W32.Navidad.16896 is a mass-mailing worm program that is very similar to W32.Navidad. The worm uses Microsoft Outlook to spread, using MAPI to reply to all Inbox messages that contain a single attachment.

The worm utilizes the existing email subject line and body, and attaches itself as Emanuel.exe.

Antivirus Protection Dates

  • Initial Rapid Release version November 29, 2000
  • Latest Rapid Release version March 03, 2008 revision 035
  • Initial Daily Certified version November 29, 2000
  • Latest Daily Certified version March 03, 2008 revision 037

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Andre Post

Discovered: November 29, 2000
Updated: February 13, 2007 11:59:59 AM
Also Known As: Navidad.E
Type: Worm

When executed, the worm does the following:

  1. Displays a dialog box with a "winking smiley face" (emoticon):


    and the title:

  2. If you are running Windows NT/2000, the worm adds the following registry key:


    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:


      and adds the value

      Win32BaseServiceMOD        \Windows\System\Wintask.exe
    • If you are running Windows NT/2000, the worm modifies the following registry key:


      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


      to equal

      \Windows\System\wintask.exe "%1" %*"
    • If you are running Windows NT/2000, the worm changes


      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


      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.


    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.

    Writeup By: Andre Post

    Discovered: November 29, 2000
    Updated: February 13, 2007 11:59:59 AM
    Also Known As: Navidad.E
    Type: Worm

    Follow the instructions in each section in the order shown. We strongly recommend that you read and understand the entire procedure before proceeding.

    To remove this worm, you must do the following:

    • Set Windows to show all files.
    • Copy Regedit.exe to Regedit.com (in most cases).
    • Edit the registry and remove keys and changes made by the worm.
    • Delete files placed on the computer by the worm.
    • Run a full system scan.

    For detailed instructions on how to do this, see the sections that follow.

    To set Windows to show all files:
    You need to do this to make sure that you can find the files installed by W32.Navidad.16896.
    1. Start Windows Explorer.
    2. Click the View menu (Windows 95/98/NT) or the Tools menu (Windows Me/2000), and then click Options or Folder Options.
    3. Click the View tab, and if necessary, uncheck "Hide file extensions for known file types."
    4. Click Show all files, and then click OK.

    To copy Regedit.exe to Regedit.com:
    If you cannot start program files, or if you see the message "Windows cannot find wintask.exe," then you'll need to copy Regedit.exe to Regedit.com.
    1. Do one of the following, depending on which operating system you are running:
      • Windows 95/98 users: Click Start, point to Programs, and click MS-DOS Prompt.
      • Windows NT/2000 users:
        1. Click Start, and click Run.
        2. Click Browse, and browse to the \Winnt\system32 folder.
        3. Double-click the Command.com file, and then click OK.
    1. Type copy regedit.exe  regedit.com and press Enter.
    2. Type start regedit.com and press Enter.
    3. Proceed to the section "To edit the registry and remove keys and changes made by the worm."

    NOTE: This will open Registry Editor in front of the DOS window. After you finish editing the registry and have closed Registry Editor, close the DOS window.

    To edit the registry and remove keys and changes made by the worm:

    CAUTION : We strongly recommend that you back up the system registry before making any changes. Incorrect changes to the registry can result in permanent data loss or corrupted files. Please make sure you modify only the keys specified in this document. For more information about how to back up the registry, please read How to back up the Windows registry before proceeding with the following steps. If you are concerned that you cannot follow these steps correctly, then please do not proceed. Consult a computer technician for more information.
    1. Start Registry Editor if necessary:
      • If you performed the procedure in the previous section, the Registry Editor is already open. Skip to step 4.
      • If it was not necessary to perform the procedures in the previous section, go on to step 2.
    2. Click Start, and click Run. The Run dialog box appears.
    3. Type regedit and click OK. Registry Editor opens.

      NOTE: If you see an error message or Registry Editor does not open, go back to and follow the instructions in the previous section.
    4. Navigate to and select the following key:

    5. Press Delete, and then click Yes to confirm.
    6. Navigate to and select the following key:

    7. Do one of the following:
      • Windows 95/98 users: In the right pane, look for and delete the following value:

        Win32BaseServiceMOD         C:\Windows\System\wintask.exe
      • Windows NT/2000 users: In the right pane, look for and delete the following value:

        Win32BaseServiceMOD         C:\Winnt\System32\wintask.exe
    8. Press Delete, and click Yes to confirm.
    9. Navigate to and select the following key:


      CAUTION: The HKEY_CLASSES_ROOT key contains many subkey entries that refer to other file extensions. One of these file extensions is .exe. Changing this extension can prevent any files ending with an .exe extension from running. Make sure you browse all the way along this path until you reach the \command subkey.

      Modify the HKEY_CLASSES_ROOT\exefile\shell\open\command subkey that is shown in the following figure:

      <<=== NOTE: This is the key that you need to modify.
    10. In the right pane, double-click the (Default) value.
    11. Delete the current value data, and then type: "%1" %* (That is, type the following characters: quote-percent-one-quote-space-percent-asterisk.)

      NOTE: Registry Editor will automatically enclose the value in quotation marks. When you click OK, the (Default) value should look exactly like this:
      ""%1" %*"

      Make sure you completely delete all value data in the command key prior to typing the correct data. If a space is left at the beginning of the entry, any attempt to run program files will result in the error message, "Windows cannot find .exe." If this happens to you, start over at the beginning of this document, making sure to completely remove the current value data.
    12. Restart the computer.

    To delete the files left by the worm:
    1. Click Start, point to Find, and click Files or Folders.
    2. Make sure that "Look in" is pointing your hard drive, or all drives if this is an option.
    3. Type emanuel*.exe in the Named box, and click Find Now.
    4. Delete any copies that you find.
    5. Click New Search.
    6. Type wintask.* in the Named box, and click Find Now.
    7. Delete any files named Wintask.exe located in the C:\Windows\System folder.

      NOTE: If Norton AntiVirus is installed and running on this computer, you may be alerted that the files are infected when you complete the previous steps. If that happens, choose Delete and ignore any subsequent Windows messages that the file cannot be deleted. (This is Windows alerting you that it cannot find the specified file. It cannot find the file because it has already been deleted by Norton AntiVirus.)
    8. Close the Find: All Files window.
    9. Right-click the Recycle Bin icon on the Windows desktop, and click Empty Recycle Bin.
    To run a full system scan:
    Start Norton AntiVirus NAV) and make sure the your virus definitions are dated November 27, 2000, or later. If they are not, then run LiveUpdate. Finally, run a full system scan. If you have any version of NAV other than NAV 2000, then make sure that NAV is set to scan all files.

    Writeup By: Andre Post