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Trojan.Favadd - Removal

Risk Level 1: Very Low

Discovered:
November 24, 2004
Updated:
February 13, 2007 12:30:17 PM
Type:
Trojan Horse
Systems Affected:
Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP

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 delete all the files detected as Trojan.Favadd.
  4. Delete the value that was added to the registry.
  5. Reset the Internet Explorer Home page.
  6. Reset the Internet Explorer Search page.
  7. Removing the button added to the Internet Explorer toolbar.
  8. Remove the links from the Favorites folder.
For specific details on each of these steps, read the following instructions.

1. To disable 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 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. To update 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. To scan for and delete the infected files
  1. Start your Symantec antivirus program 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 Trojan.Favadd, write down the path and file name and then click Delete.

    Note: If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix this, run the scan in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode." Once you have restarted in Safe mode, run the scan again.

    (After the files are deleted, you can leave the computer in Safe mode and proceed with section 4. When that is done, restart the computer in Normal mode.)


4. To delete the value from the registry


WARNING: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read the document, "How to make a backup of the Windows registry," for instructions.
  1. Click Start, and then click Run. (The Run dialog box appears.)
  2. Type regedit

    Then click OK. (The Registry Editor opens.)

  3. Navigate to the key:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Extensions\(10954C80-4F0F-11d3-B17C-00C0DFE39736)

  4. In the right pane, delete the values:

    "ButtonText"="Search cracks at CrackSpider.NET"
    "MenuText"="Search cracks at CrackSpider.NET"
    "MenuStatusBar"="Search cracks at CrackSpider.NET"
    "ClSid"="(1FBA04EE-3024-11d2-8F1F-0000F87ABD16)"
    "Default Visible"="Yes"
    "Exec"="[URL on the domain crackspider.net]"
    "HotIcon"="%Windir%\crcspider.ico"
    "Icon"="%Windir%\crcspider.ico"


  5. Navigate to the key:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Extensions\CmdMapping

  6. In the right pane, delete the value:

    "{10954C80-4F0F-11d3-B17C-00C0DFE39736}" = "8193"

  7. Navigate to the key:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Search

  8. In the right pane, delete the value:

    "SearchAssistant"="[URL on the domain crackspider.net]"

  9. Navigate to the key:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main

  10. In the right pane, delete the value:

    "Search Bar"="[URL on the domain crackspider.net]"

  11. Exit the Registry Editor.



5. To reset the Internet Explorer home page
  1. Start Microsoft Internet Explorer.
  2. Connect to the Internet, and then go to the page that you want to set as your home page.
  3. Click Tools > Internet Options.
  4. In the Home page section of the General tab, click Use Current > OK.

For additional information, or if this procedure does not work, read the Microsoft® Knowledge Base article, "Home Page Setting Changes Unexpectedly, or You Cannot Change Your Home Page Setting, Article ID 320159."

    6. To reset the Internet Explorer Search page
    Follow the instructions for your version of Windows.

    Windows 98/Me/2000
    1. Start Microsoft Internet Explorer.
    2. Click the Search button on the toolbar.
    3. In the Search pane, click Customize.
    4. Click Reset.
    5. Click Autosearch Settings.
    6. Select a search site from the drop-down list, and then click OK.
    7. Click OK.

    Windows XP
    Because Windows XP is set by default to use animated characters in the search, how you do this can vary. Read all the instructions before you start.
    1. Start Microsoft Internet Explorer.
    2. Click the Search button on the toolbar.
    3. Do one of the following:
      • If the pane that opens looks similar to this picture:





        click the word Customize. Then skip to step h.

      • If the pane that opens has the words "Search Companion" at the top, and the center looks similar to this picture:





        click the Change preferences link as shown above. Proceed with step d.

    4. Click the Change Internet search behavior link.
    5. Under "Internet Search Behavior," click With Classic Internet Search.
    6. Click OK. Then close Internet Explorer. (Close the program for the change to take effect.)
    7. Start Internet Explorer. When the search pane opens, it should now look similar to this:





      Click the word Customize, and then proceed with the next step.

    8. In the Search pane, click Customize.
    9. Click Reset.
    10. Click Autosearch Settings.
    11. Select a search site from the drop-down list, and then click OK.
    12. Click OK.
    13. Do one of the following:
      • If you were using (or want to continue using) the "Classic Internet Search" panel, stop here (or proceed with the next section).
      • If you want to go back to the "Search Companion" search (it usually has an animated character at the button), proceed with step n.

    14. Click the word Customize again.
    15. In the "Customize Search Settings" window, click Use Search Companion > OK.
    16. Close Internet Explorer. The next time you open it, it will again use the Search Companion

    7. Removing the Button added to the Internet Explorer toolbar
    a. Start Microsoft Internet Explorer
    b. Right Click the Button and select Customise.
    c. Select Search Cracks at CrackSpider.NET in the Right Pane.
    d. Click Remove.


    8. Removing links added to Favourites
    1. Start Internet Explorer.
    2. Click Favorites, and then Organize Favorites.
    3. Delete the folder named "cracks", which contains the links to the Web sites that the Trojan added.


    Writeup By: Rodney Andres

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