Adware.Wengs

SUMMARY

Behavior

Adware.Wengs is an adware program that changes the Internet Explorer home page and collects information for advertising purposes.

Symptoms

Your home page is changed to we.cn.gs.

Transmission

This adware component must be manually installed, or installed as a component of another program that you install.

Protection

• Virus Definitions (LiveUpdate™ Weekly) October 1, 2003
• Virus Definitions (Intelligent Updater) October 1, 2003

TECHNICAL DETAILS

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

1. Copies itself to %System%Wupdate.exe.
   
   

   ---

   Note: %System% is a variable. The worm locates the folder (by default, this is C:WindowsSystem or C:WinntSystem32) and copies itself to that location.

   ---

   
   
2. Adds the value:
   
   "Windows Update" =  %System%Wupdate.exe
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   so that the adware runs when you start Windows.
   
   
3. Changes the Internet Explorer home page to we.cn.gs.
   
   
4. Opens a browser window and displays a flash animation downloaded from the Internet.
   
   
5. Attempts to access the following URL at 3721.com, which redirects users to Yahoo china (http: //cn.yahoo.com).
   
   http:// cns.3721.com/cns.dll?fw=cm2&name=%D1%C5%BB%A2&pid=U_angelye_19721
   
   
6. May download itself, or its updated version, from we.cn.gs.

REMOVAL

---

Note: Removing this adware component from the system will likely cause the program that installed it to not function as intended. The uninstaller generally identifies the programs that will not work after uninstallation.

---

1. Update the virus definitions.
2. Run a full system scan and delete all the files detected as Adware.Wengs.
3. Delete the value from the Registry.
4. Restore the Internet Explorer settings

For specific details on each of these steps, read the following instructions.

1. 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.

2. Scanning for and deleting the infected files

1. Start Norton AntiVirus and make sure that it is configured to scan all the files. For more information, read the document, "How to configure Norton AntiVirus to scan all files."
2. Run a full system scan.
3. If any files are detected as infected with Adware.Wengs, click Delete.
   
   

3. Deleting the value from the registry

CAUTION: 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_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
4. In the right pane, delete any values pertaining to "Windows Update."
   
   
5. Exit the Registry Editor.

4. Restoring the Internet Explorer settings

1. Start Microsoft Internet Explorer.
2. Connect to the Internet and 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.
5. On the Programs tab, click Reset Web Settings.