VBS.Bootconf

SUMMARY

VBS.Bootconf is a Trojan horse that modifies the TCP/IP settings to point to a different address. It also changes the Internet Explorer home page and search page to connect to www.royalsearch.net.

VBS.Bootconf is written in Visual Basic Script.

Protection

• Virus Definitions (LiveUpdate™ Weekly) November 5, 2003
• Virus Definitions (Intelligent Updater) November 3, 2003

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

When the VBS.Bootconf is executed, it performs the following actions:

1. Adds the following entries to the HOSTS file:
   
   <IP address> auto.search.msn.com
   <IP address> search.msn.com
   <IP address>  msn.com
   <IP address> www.msn.com
   
   which redirects the above URLs to a predetermined IP address.
   
   
2. Adds or modifies the values:
   
   • "Start Page" = "www.royalsearch.net"
   • "Search Page" = "www.royalsearch.net/search.html"
   • "Search Bar" = "www.royalsearch.net/search.html"
   • "Use Search Asst" = "no"
     
     in the registry key:
     
     HKEY_LOCAL_MACHINESoftwareMicrosoftInternet ExplorerMain
     
     
3. Adds the value:
   
   "SearchURL" = "www.royalsearch.net/search.php?q=%s"
   
   in the registry key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftInternet Explorer
   
   
4. Modifies the values:
   
   • "SearchAssistant" = "www.royalsearch.net/search.html"
   • "CustomizeSearch" = "www.royalsearch.net/search.html"
     
     in the registry key:
     
     HKEY_LOCAL_MACHINESoftwareMicrosoftInternet ExplorerSearch
     
     
5. Modifies the values:
   
   • "Start Page" = "www.royalsearch.net"
   • "Search Page" = "www.royalsearch.net/search.html"
   • "Default_Page_URL" = "www.royalsearch.net"
   • "Default_Search_URL" = "www.royalsearch.net/search.html"
     
     in the registry key:
     
     HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerMain
     
     
6. Modifies the values:

• "SearchAssistant" = "www.royalsearch.net/search.html"
• "CustomizeSearch" = "www.royalsearch.net/search.html"
• "Default_Search_URL" = "www.royalsearch.net/search.html"
  
  in the registry key:
  
  HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerSearch

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

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

1. Update the definitions.
2. Restart the computer in Safe mode or VGA mode.
3. Run a full system scan and delete all the files detected as VBS.Bootconf.
4. Delete the value that was added to the registry.
5. Restore the Internet Explorer settings.
6. Reverse the changes that were made to the Hosts file.
   

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

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


2. Restarting the computer in Safe mode or VGA mode
Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode or VGA mode.

• For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
• For Windows NT 4 users, restart the computer in VGA mode.

3. Scanning for and deleting the 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 VBS.Bootconf, click Delete.

4. Deleting the value from the registry

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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.

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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_MACHINESoftwareMicrosoftInternet ExplorerMain
   
   
4. In the right pane, delete the values:
   
   • "Start Page" = "www.royalsearch.net"
   • "Search Page" = "www.royalsearch.net/search.html"
   • "Search Bar" = "www.royalsearch.net/search.html"
   • "Use Search Asst" = "no"
     
     
5. Navigate to the key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftInternet Explorer
   
   
6. In the right pane, delete the values:
   
   "SearchURL" = "www.royalsearch.net/search.php?q=%s"
   
   
7. Navigate to the key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftInternet ExplorerSearch
   
   
8. In the right pane, delete the values:
9. • "SearchAssistant" = "www.royalsearch.net/search.html"
   • "CustomizeSearch" = "www.royalsearch.net/search.html"
     
     
10. Navigate to the key:
    
    HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerMain
    
    
11. In the right pane, delete the values:
    
    • "Start Page" = "www.royalsearch.net"
    • "Search Page" = "www.royalsearch.net/search.html"
    • "Default_Page_URL" = "www.royalsearch.net"
    • "Default_Search_URL" = "www.royalsearch.net/search.html"
      
      
12. Navigate to the key:
    
    HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerSearch
    
    
13. In the right pane, delete the values:
    
    • "SearchAssistant" = "www.royalsearch.net/search.html"
    • "CustomizeSearch" = "www.royalsearch.net/search.html"
    • "Default_Search_URL" = "www.royalsearch.net/search.html"
      
      
14. Exit the Registry Editor.

5. Restoring the Internet Explorer settings
Some of the changes that the Trojan makes to the registry will modify some Internet Explorer settings. One of the settings it changes is to the home page.

To reset the home page:

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, and then click Internet Options.
4. In the Home page section of the General tab, click Use Current, and then click OK.

If you notice any other problems when using Internet Explorer, change these settings within the program. See your Internet Explorer documentation for instructions.


6. Reversing the changes made to the Hosts file

---

Note: The location of the Hosts file may vary and some computers may not have this file. For example, if the file exists in Windows 98, it will usually be in C:Windows, and it is located in the C:WINNTsystem32driversetc folder in Windows 2000. There may also be multiple copies of this file in different locations.

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Follow the instructions for your operating system:

• Windows 95/98/Me/NT/2000
  1. Click Start, point to Find or Search, and then click Files or Folders.
  2. Make sure that "Look in" is set to (C:) and that "Include subfolders" is checked.
  3. In the "Named" or "Search for..." box, type:
     
     hosts
     
     
  4. Click Find Now or Search Now.
  5. For each one that you find, right-click it, and then click "Open With."
  6. Deselect the "Always use this program to open this program" check box.
  7. Scroll through the list of programs and double-click Notepad.
  8. Look for the following lines and delete them, if found:
     
     <IP address> auto.search.msn.com
     <IP address> search.msn.com
     <IP address> msn.com
     <IP address> www.msn.com
     
  9. Close Notepad and save your changes when prompted.
     
     
• Windows XP
  1. Click Start, and then click Search.
  2. Click All files and folders.
  3. In the "All or part of the file name" box, type:
     
     hosts
     
     
  4. Verify that "Look in" is set to "Local Hard Drives" or to (C:).
  5. Click "More advanced options."
  6. Check "Search system folders."
  7. Check "Search subfolders."
  8. Click Search.
  9. Click Find Now or Search Now.
  10. For each one that you find, right-click it, and then click "Open With."
  11. Deselect the "Always use this program to open this program" check box.
  12. Scroll through the list of programs and double-click Notepad.
  13. Look for the following lines and delete them, if found:
      
      <IP address> auto.search.msn.com
      <IP address> search.msn.com
      <IP address> msn.com
      <IP address> www.msn.com
      
      
  14. Close Notepad and save your changes when prompted.