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Adware.BestSearch

Adware.BestSearch

Updated:
February 13, 2007
Publisher:
best-search.us
Risk Impact:
Low
File Names:
MegaInstaller.exe
Systems Affected:
Windows

Behavior


Adware.BestSearch is a search hijacker that is installed as a Browser Helper Object.

Symptoms


Your Symantec program detects Adware.BestSearch.

Behavior


The Adware.BestSearch installer must be executed. The installer may be embedded in a HTML Help (.chm) file.

Antivirus Protection Dates

  • Initial Rapid Release version October 02, 2014 revision 022
  • Latest Rapid Release version March 23, 2017 revision 037
  • Initial Daily Certified version April 27, 2005
  • Latest Daily Certified version March 23, 2017 revision 041
  • Initial Weekly Certified release date April 27, 2005
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

When Adware.BestSearch is executed, it performs the following actions:

  1. Creates the following files:

    %UserProfile%\Local Settings\Temp\MegaHost.dll
    %UserProfile%\Local Settings\Temp\MegaInstaller.exe
    %UserProfile%\Local Settings\Temp\temp.dll

    Notes:
    %UserProfile% is a variable that refers to the current user's profile folder. By default, this is C:\Documents and Settings\<Current User> (Windows NT/2000/XP).
  2. Creates the following registry subkeys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}
    HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}\InprocServer32
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MegaSearch
    HKEY_CURRENT_USER\Software\MegaHost

  3. Adds the values:

    "@" = "%UserProfile%\Local Settings\Temp\MegaHost.dll"
    "ThreadingModel" = "Apartment"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}\InprocServer32

  4. Adds the value:

    "@" = "Mega!"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}

  5. Adds the values:

    "UninstallString" = "%UserProfile%\Local Settings\Temp\MegaInstaller.exe /u"
    "DisplayName" = "MegaSearch"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MegaSearch

  6. Adds the value:

    "Use Search Asst" = "no"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main

  7. Adds the values:

    "page" = "0x00000001"
    "Use Search Asst" = "no"
    "SearchAssistant" = "http:/ /ie.search.msn.com/{SUB_RFC1766}/srchasst/srchasst.htm"
    "Start Page" = "http:/ /www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome"
    "cid" = "cb719ff8-7813-4a5e-916f-66692534204e"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\MegaHost

  8. Modifies the value:

    "SearchAssistant" = "http:/ /best-search.us/?page=search&pid=sext01"

    in the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Search

  9. Displays pop-up ads.



The following instructions pertain to all Symantec antivirus products that support Security Risk detection.
  1. Update the definitions.
  2. Restart the computer in Safe mode.
  3. Run a full system scan.
  4. Delete the values added to the registry.
  5. Reset the modified registry values.
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 restart the computer in Safe mode
Shut down the computer, and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode. For instructions, read "How to start the computer in Safe Mode ."

3. To run the scan
  1. Start your Symantec antivirus program, and then run a full system scan.
  2. If any files are detected as Adware.BestSearch, 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 see only a message box that gives the results of the scan. If you have questions about this situation, contact your network administrator.
    • Exclude (Not recommended)
      If you click this button, it will set the threat 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 threat 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 threat for this scan only; the threat will be detected again the next time that you run a scan.

      To delete the security risk
      1. Click its file name (under the Filename column).
      2. In the Item Information box that appears, write down the full path and file name.
      3. Use Windows Explorer to locate and delete the file.

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

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 > Run.

  2. Type regedit

    Then click OK.

  3. Navigate to and delete the following keys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}
    HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}\InprocServer32
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{8BC6346B-FFB0-4435-ACE3-FACA6CD77816}
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MegaSearch
    HKEY_CURRENT_USER\Software\MegaHost

  4. Navigate to the registry key:

    HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main

  5. In the right pane, delete the value:

    "Use Search Asst" = "no"

  6. Navigate to and restore the following the following values, if known:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Search\"SearchAssistant"

  7. Exit the Registry Editor.