Trojan.Bookmarker.G

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Discovered: March 19, 2004
Updated: February 13, 2007 12:19:42 PM
Type: Trojan Horse
Systems Affected: Windows


Trojan.Bookmarker.G modifies the Internet Explorer settings, adds bookmarks to Internet Explorer Favorites, and downloads other programs.

Note: Virus definitions dated July,10,2005 or earlier may detect this threat as Adware.OleHelp.

Antivirus Protection Dates

  • Initial Rapid Release version March 22, 2004
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version March 22, 2004
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date March 24, 2004

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

Writeup By: Paul Mangan

Discovered: March 19, 2004
Updated: February 13, 2007 12:19:42 PM
Type: Trojan Horse
Systems Affected: Windows


When Trojan.Bookmarker.G is executed, it does the following:

  1. Copies itself to one of the following files:
    • %Windir%\Olehelp.exe
    • %System%\olehelp.exe.

      Note:
    • %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
    • %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows (Windows 95/98/Me/XP) or C:\Winnt (Windows NT/2000).

  2. Adds pornographic bookmarks to the Internet Explorer Favorites.

  3. Downloads and executes Cihost.exe, which contains Trojan.Linst and Adware.IEHelpPage.

  4. Modifies the value:

    "Search Assistant" = "[http://]power-search.info/[REMOVED]/sp.html"

    in the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Search

  5. Modifies the value:

    "Start Page" = "[http://]power-search.info/[REMOVED]/sp.html"

    in the registry subkey:

    HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main

  6. Modifies the value:

    "Search Page" = "[http://]power-search.info/[REMOVED]/sp.html"

    in the registry subkey:

    HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main

  7. Modifies the value:

    "Use Search Asst" = "no"

    in the registry subkey:

    HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main

  8. Modifies the value:

    "Search Bar" = "[http://]power-search.info/[REMOVED]/sp.html"

    in the registry subkey:

    HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main

  9. Modifies the value:

    "Provider" = "gogl"

    in the registry subkey:

    HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\SearchUrl

  10. Modifies the value:

    (Default) = "[http://]power-search.info/[REMOVED]/sp.html"

    in the registry subkey:

    HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\SearchUrl

  11. Adds the value:

    "olehelp" = "%windir%\olehelp.exe"
    or
    "svchost" = "%SYSTEM%\olehelp.exe"

    to the registry subkey:

    HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Run

    so that the adware runs every time Windows starts.

  12. Opens Internet Explorer, at intervals, to the page [http: //]toteen.com/[REMOVED]/in.cgi?tiny.

  13. May download and execute dialers.


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.

Writeup By: Paul Mangan

Discovered: March 19, 2004
Updated: February 13, 2007 12:19:42 PM
Type: Trojan Horse
Systems Affected: 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. Restart the computer in Safe mode or VGA mode.
  4. Run a full system scan and delete all the files detected as Trojan.Bookmarker.G.
  5. Reverse the changes made to the registry.
  6. Reset the Internet Explorer settings.
  7. Reset the Intenet Explorer home page.
  8. Reset the Internet Explorer Search page.
  9. Delete the pornographic bookmarks.
For 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 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. Restarting the computer in Safe mode or VGA mode

Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode or VGA mode.
  • For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
  • For Windows NT 4 users, restart the computer in VGA mode.
4. Scanning for and deleting 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.Bookmarker.G, click Delete.

5. Reversing the changes made to 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.

Click Start, and then click Run.
  1. Type regedit

    Then click OK.

  2. Navigate to the key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

  3. In the right pane, delete the value:

    "olehelp"="%olehelp%\olehelp.exe"

    and

    "svchost" = "%SYSTEM%\olehelp.exe"

  4. Exit the Registry Editor.

  5. Restart the computer in Normal mode. For instructions, read the section on returning to Normal mode in the document, "How to start the computer in Safe Mode."


7. Resetting 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 the Tools menu > Internet Options.
  4. In the Home page section of the General tab, click Use Current, and then click 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."


    8. Resetting 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 perform 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 to 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. (You must 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 go on to 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 go on to the next section).
      • If you want to go back to the "Search Companion" search (it usual has an animated character at the button), go on to step n.

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

    9. Remove the pornographic bookmarks
    1. In Internet Explorer, click on Favorites on the toolbar.
    2. Right click on any unwanted bookmarks and select to delete them.


    Writeup By: Paul Mangan