W32.Benpao.Trojan - Removal

These instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Update the virus definitions.
2. Run a full system scan and delete all the files detected as W32.Benpao.Trojan.
3. Reverse the changes that the Trojan made to the registry.

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

NOTE: If, when following the instructions in Steps 1 and 2 below, either LiveUpdate or your Symantec antivirus program does not start, use the following alternate procedure:
1. Restart the computer in Safe mode. All the Windows 32-bit operating systems, except Windows NT, can be restarted in Safe mode. For instructions on how to do this, read the document, "How to start the computer in Safe Mode."
2. Follow the instructions in Step 3.
3. Restart the computer in Normal mode.
4. Follow the instructions in Steps 1 and 2.

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 the 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), in the "Protection" section, at the top of this writeup.
• 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), in the "Protection" section, at the top of this writeup.
  
  The Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

2. 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.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan All Files."
2. Run a full system scan.
3. If any files are detected as infected with W32.Benpao.Trojan, click Delete.

3. Reversing the changes made to the registry

Because the Trojan modified the registry so that the Trojan runs when you try to execute many file types, first make a copy of the Registry Editor as a file with the .com extension, and then run it.

CAUTION: This Trojan makes numerous registry changes that must be reversed. The recommended changes in steps g through r are general. The exact path and other text (such as quotation marks) to which you need to change these can vary with both your installation and the operating system. If you have questions on exactly what a registry value should be, consult a qualified computer technician.

1. Do one of the following, depending on which version of Windows you are running:
   • Windows 95/98 users:
     1. Click Start.
     2. Point to Programs.
     3. Click the MS-DOS Prompt. (A DOS window opens at the C:\Windows prompt.) Proceed to step b of this section.
   • Windows Me users:
     1. Click Start.
     2. Point to Programs.
     3. Point to Accessories.
     4. Click the MS-DOS Prompt. (A DOS window opens at the C:\Windows prompt.) Proceed to step b of this section.
   • Windows NT/2000 users:
     1. Click Start, and then click Run.
     2. Type command, and then press Enter. (A DOS window opens.)
     3. Type cd \winnt, and then press Enter.
     4. Go to step b of this section.
   • Windows XP users:
     1. Click Start, and then click Run.
     2. Type command, and then press Enter. (A DOS window opens.)
     3. Type the following:
        
        cd\
        cd \windows
        
        Press Enter after typing each one.
        
     4. Proceed to step b of this section.
        
        
2. Type:
   
   copy regedit.exe regedit.com
   
   And then press Enter.
   
3. Type:
   
   start regedit.com
   
   And then press Enter. (The Registry Editor opens in front of the DOS window.)
   
4. Before continuing, Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. For instructions, read the document, "How to make a backup of the Windows registry."
   
5. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
6. In the right pane, delete the value:
   
   ExplorerBen C:\%dir%\kx.exe
   
7. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\Software\Classes\chm.file\shell\open\command
   
8. Change the value:
   
   (Default) C:\%dir%\.exe
   
   to:
   
   (Default) %Windir%\hh.exe %1
   
9. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\Software\Classes\scrfile\shell\open\command
   
10. Change the value:
    
    (Default) C:\%dir%\d.exe %1
    
    to:
    
    (Default) %1 /s
    
11. Navigate to the key:
    
    HKEY_LOCAL_MACHINE\Software\Classes\regfile\shell\open\command
    
12. Change the value:
    
    (Default) C:\%dir%\w.exe %1
    
    to:
    
    (Default) regedit.exe %1
    
13. Navigate to the key:
    
    HKEY_LOCAL_MACHINE\Software\Classes\exefile\shell\open\command
    
14. Change the value:
    
    (Default) C:\%dir%\d.exe %1 %
    
    to:
    
    (Default) %1 %
    
15. Navigate to the key:
    
    HKEY_LOCAL_MACHINE\Software\Classes\txtfile\shell\open\command
    
16. Change the value:
    
    (Default) C:\%dir%\F.exe %1
    
    to:
    
    (Default) = %Windir%\Notepad.exe %1
    
17. Navigate to the key:
    
    HKEY_LOCAL_MACHINE\Software\Classes\inifile\shell\open\command
    
18. Change the value:
    
    (Default) C:\%dir%\e.exe %1
    
    to:
    
    (Default) %Windir%\Notepad.exe %1
    
19. Exit the Registry Editor.

Technical Details