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Discovered: March 15, 2005
Updated: February 13, 2007 12:35:28 PM
Type: Trojan Horse
Systems Affected: Windows

Trojan.StartPage.M is a Trojan horse that modifies settings in Internet Explorer.

Note: Virus definitions dated prior to March 15, 2005 may detect this as Trojan.StartPage.

Antivirus Protection Dates

  • Initial Rapid Release version March 15, 2005
  • Latest Rapid Release version November 04, 2019 revision 019
  • Initial Daily Certified version March 15, 2005
  • Latest Daily Certified version November 04, 2019 revision 065
  • Initial Weekly Certified release date March 16, 2005

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

Technical Description

When Trojan.StartPage.M is executed, it performs the following actions:

  1. Drops the file %Temp%\se.dll.

    Note: %Temp% is a variable that refers to the Windows temporary folder. By default, this is C:\Windows\TEMP (Windows 95/98/Me/XP) or C:\WINNT\Temp (Windows NT/2000).

  2. Registers itself as a Browser Helper Object by creating and populating the following registry subkeys:


  3. Adds the value:

    "CLSID" = "{2862736E-7B27-418A-A4E8-F13FB2E8C945}"

    to the registry subkeys:


    to register itself as a protocol filter. This enables the Trojan to modify content displayed in Internet Explorer.

  4. Adds the value:

    "sp" = "rundll32 %temp%\se.dll,DllInstall"

    to the registry subkey:


    so that it is executed every time Windows starts.

  5. Adds the value:

    "Search Bar" = "res://%temp%\se.dll/sp.htm;"

    to the registry subkeys:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Main

    to modify the search settings in Internet Explorer.

  6. Displays a Web page contained in se.dll, when Internet Explorer is started.


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.


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.StartPage.M.
  4. Delete any values added to the registry.
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:
When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable 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 document: Virus Definitions (LiveUpdate).
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. 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 document: Virus Definitions (Intelligent Updater).

    The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

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.StartPage.M, click Delete.

    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, restart the computer in Normal mode and proceed with section 4.

4. To delete the value from the registry
Important: 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 subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

  4. Navigate to the subkey:


  5. In the right pane, delete the value:

    "sp" = "rundll32 %temp%\se.dll,DllInstall"

  6. Navigate to the subkeys:


  7. In the right pane, delete the value:

    "CLSID" = "{2862736E-7B27-418A-A4E8-F13FB2E8C945}"

  8. Navigate to and delete the following subkeys:


  9. 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 the following picture, click the word Customize and proceed to step h:

      • If the pane that opens has the words "Search Companion" at the top, and the center looks similar to the following picture, click the Change preferences link and 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 look similar to the following picture:

      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.

    Writeup By: Paul Mangan