W97M.Chameleon.I

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Discovered: February 06, 2004
Updated: February 13, 2007 12:17:06 PM
Also Known As: Macro.Word97.Chameleon.c [Kasp, W97M/Chameleon.I [F-Prot], W97M_CHAMELEON.C [Trend], W97M/Chameleon.C.dr [GeCAD]
Systems Affected: Mac, Windows


W97M.Chameleon.I is a macro virus that infects Microsoft Word documents and the Normal.dot template when an infected document is opened.

Antivirus Protection Dates

  • Initial Rapid Release version February 06, 2004
  • Latest Rapid Release version February 06, 2004
  • Initial Daily Certified version February 06, 2004
  • Latest Daily Certified version February 06, 2004
  • Initial Weekly Certified release date February 11, 2004

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

Writeup By: Keiichi Ito

Discovered: February 06, 2004
Updated: February 13, 2007 12:17:06 PM
Also Known As: Macro.Word97.Chameleon.c [Kasp, W97M/Chameleon.I [F-Prot], W97M_CHAMELEON.C [Trend], W97M/Chameleon.C.dr [GeCAD]
Systems Affected: Mac, Windows


When a document infected with W97M.Chameleon.I is opened, the virus performs the following actions:

  1. Checks the value:

    "Level"

    in the registry key:

    HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Security

    to see if it is set with non-empty, string data. If so, the virus disables the Word's menu items:
    • Tool > Macro
    • Tool > Templates and Add-ins...
    • Format > Style Gallery...


      otherwise it disables the menu item:
    • Macro > Security...

  2. Disables user interrupts to Visual Basic for Application procedures, which can be done by pressing ESC, or the CTRL + BREAK keys.

  3. Disables the built-in warning message in Microsoft Word, which is displayed when opening a document that might contain macro viruses.

  4. Disables the option to display a prompt message when you open documents that are not in Microsoft Word format.

  5. Disables the option to display a prompt message when saving changes to the Normal.dot template.

  6. Disables the option to display a prompt message for document property information when saving a document.

  7. Infects the Normal.dot template.

  8. Drops the file, Quiet.vbs, in the C:\Windows\Start Menu\Programs\Startup folder, if present.


    Note: The Quiet.vbs file contains the virus known as VBS.Chameleon.C.

  9. Creates the Quiet.dll file in the folder C:\Windows\System, if present.


    Note: This file is empty and does not contain virus code.


Writeup By: Keiichi Ito

Discovered: February 06, 2004
Updated: February 13, 2007 12:17:06 PM
Also Known As: Macro.Word97.Chameleon.c [Kasp, W97M/Chameleon.I [F-Prot], W97M_CHAMELEON.C [Trend], W97M/Chameleon.C.dr [GeCAD]
Systems Affected: Mac, Windows


The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Disable System Restore (Windows Me/XP).
  2. Update the virus definitions.
  3. Run a full system scan and repair all the files detected as W97M.Chameleon.I and VBS.Chameleon.C.
  4. Delete Quiet.dll.

For specific details on each of these steps, read the following instructions.

1. Disabling System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
Note: When you are completely finished with the removal procedure and you are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.

2. Updating the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:

  • Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).

    The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. Scanning for and repairing the infected files
  1. Start your Symantec antivirus software and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected as infected with W97M.Chameleon.I or VBS.Chameleon.C, click Repair.

4. Deleting Quiet.dll
Delete the file, C:\Windows\System\Quiet.dll.


Writeup By: Keiichi Ito