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Updated: February 13, 2007 11:47:39 AM
Type: Adware
Publisher: Global Netcom GmbH
Risk Impact: High
Systems Affected: Windows


Adware.Webprefix is an Internet Explorer browser helper object that displays advertisements and may send information about the compromised computer to a controlling web server.


One or more files detected as Adware.Webprefix.


This file must be manually installed.

Antivirus Protection Dates

  • Initial Rapid Release version October 02, 2014 revision 022
  • Latest Rapid Release version May 07, 2019 revision 006
  • Initial Daily Certified version January 12, 2006
  • Latest Daily Certified version May 07, 2019 revision 008
  • Initial Weekly Certified release date January 18, 2006

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

Technical Description

When Adware.Webprefix is installed, it performs the following actions:

  1. Creates the file %System%\[FILE NAME].dll.

    • %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).
    • [FILE NAME] is made up from other filenames present in the %System% folder.

  2. Creates the following registry subkeys:

    \Browser Helper Objects\[RANDOM_GUID]

  3. Adds the values:

    "Enable Browser Extensions" = "yes"
    "WebPrefix" = "02266 - ROUTE4FREE"
    "Offline Folder" = "[UNIQUE ID]"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main

    where [UNIQUE ID] is the id used to identify the Adware to it's controlling server.

  4. Contacts the following site to get configuration information and send system details such as the current service pack installed:

  5. Displays advertisements.


The following instructions pertain to all Symantec antivirus products that support security risk detection.

  1. Update the definitions.
  2. Run a full system scan.
  3. Delete any values added to the registry.
For specific details on each of these steps, read the following instructions.

1. To update the definitions
To obtain the most recent definitions, start your Symantec program and run LiveUpdate.

2. To run the scan
  1. Start your Symantec antivirus program, and then run a full system scan.
  2. If any files are detected, and depending on which software version you are using, you may see one or more of the following options:

    Note: This applies only to versions of Norton AntiVirus that support security risk detection. If you are running a version of Symantec AntiVirus Corporate Edition that supports security risk detection, and security risk detection has been enabled, you will only see a message box that gives the results of the scan. If you have questions in this situation, contact your network administrator.
    • Exclude (Not recommended): If you click this button, it will set the risk so that it is no longer detectable. That is, the antivirus program will keep the security risk on your computer and will no longer detect it to remove from your computer.

    • Ignore or Skip: This option tells the scanner to ignore the risk for this scan only. It will be detected again the next time that you run a scan.

    • Cancel: This option is new to Norton Antivirus 2005. It is used when Norton Antivirus 2005 has determined that it cannot delete a security risk. This Cancel option tells the scanner to ignore the risk for this scan only, and thus, the risk will be detected again the next time that you run a scan.

      To actually delete the security risk:
      • Click its file name (under the Filename column).
      • In the Item Information box that displays, write down the full path and file name.
      • Then use Windows Explorer to locate and delete the file.

    • Delete: This option will attempt to delete the detected files. In some cases, the scanner will not be able to do this.
      • If you see a message, "Delete Failed" (or similar message), manually delete the file.
      • Click the file name of the risk that is under the Filename column.
      • In the Item Information box that displays, write down the full path and file name.
      • Then use Windows Explorer to locate and delete the file.

  3. Make a note of any file names detected as Adware.Webprefix as you will need them for Step 3 below.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do 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 the next section.

Warning messages may be displayed when the computer is restarted, since the risk may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.

3. 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. Read the document: How to make a backup of the Windows registry .
  1. Click Start > Run.
  2. Type regedit

    Then click OK.

    Note: If the registry editor fails to open the risk may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.

  3. Navigate to the subkey:


  4. Click Edit > Find.

  5. In the "Find what" text box, type the file name of the .dll file that was detected as Adware.Webprefix in Step 2 above.

  6. If you find an entry of the form:

    "(Default)" = "%System%\[FILE NAME].dll

    in the registry subkey:


    then record the [RANDOM_GUID] value referred to in this subkey.

    Next, in the left pane, delete the subkey which refers to this value:


    If you detected more than one .dll file in Step 2 above, click Edit > Find and repeat the search, as there may be more than one subkey. Delete any subkeys that are found.

  7. Navigate to and delete the subkeys:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{[RANDOM_GUID]}

    where [RANDOM_GUID] matches one of the values found in the previous searches carried out in Step 3(f) above.

  8. Navigate to the subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main

  9. In the right pane, delete the values:

    "Enable Browser Extensions" = "yes"
    "WebPrefix" = "02266 - ROUTE4FREE"
    "Offline Folder" = "[UNIQUE ID]"

  10. Exit the Registry Editor.