VBS.Inker

SUMMARY

VBS.Inker is a VBS script worm that attempts to perform malicious acts, including attempts at a mass-mailing.

Protection

• Virus Definitions (LiveUpdate™ Weekly) June 29, 2005
• Virus Definitions (Intelligent Updater) June 25, 2005

Threat Assessment

Wild

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

Damage

• Damage Level: Low
• Payload: Swaps mouse buttons, disables desktop display, and disables the keyboard and mouse.
• Modifies Files: Overwrites files with the extensions .vbs, .bat, .txt, .vbe, or .ini
• Compromises Security Settings: Deletes security-related folders and files.

Distribution

• Distribution Level: Low
• Subject of Email: Varies.
• Name of Attachment: Varies.

TECHNICAL DETAILS

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

1. Creates some or all of the following files:
   
   
   • %Windir%Ip.bat
   • C:WINDOWSIpnuker.vbs
   • C:mircIpnuker.vbs
   • %Windir%IpUserCreate.bat
   • C:[RANDOM NUMBER].txt
   • %Windir%IpUser.bat
     
     Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:Windows or C:Winnt.
     
     
2. Adds the values:
   
   "WindosXp" = "Wscript.exe [SCRIPT NAME]"
   "DisableKeyboard" = "Rundll32.exe Keyboard,Disable"
   "DisableMouse" = "Rundll32.exe Mouse,Disable"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   so that the threat runs every time Windows starts and attempts to disable the keyboard and mouse.
   
   
3. Executes a command that swaps the mouse buttons.
   
   
4. Deletes the folder C:Program filesNorton AntiVirus, if present.
   
   
5. Modifies the value:
   
   "NoDesktop" = "1"
   
   in the registry subkey:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionPoliciesExplorer
   
   to hide the desktop.
   
   
6. Sets the following registry entries:
   
   HKEY_CLASSES_ROOTVBSFileDefaultIcon"DefaultIcon" = "shell32.dll,-298"
   HKEY_CLASSES_ROOT xtfileDefaultIcon"DefaultIcon" = "shell32.dll,-16"
   KEY_CLASSES_ROOTinifileDefaultIcon"DefaultIcon" = "shell32.dll,-16"
   HKEY_CLASSES_ROOTmpegfileDefaultIcon"DefaultIcon" = "shell32.dll,-52"
   HKEY_CLASSES_ROOTjpegfileDefaultIcon"DefaultIcon" = "shell32.dll,-52"
   HKEY_CLASSES_ROOTmp3fileDefaultIcon"DefaultIcon" = "shell32.dll,-512"
   HKEY_CLASSES_ROOTinffileDefaultIcon"DefaultIcon" = "shell32.dll,-5"
   
   which resets the .vbs, .txt., .ini, .mpg, .jpg, .mp3 and .inf icons.
   
   
7. Modifies the value:
   
   "(Default)" = "%System%System32WScript.exe"
   
   in the registry subkeys:
   
   HKEY_CLASSES_ROOTVBSFileShellCommand
   HKEY_CLASSES_ROOTVBSFileEditCommand
   HKEY_CLASSES_ROOT xtfileshellopencommand
   HKEY_CLASSES_ROOT xtfileshellprintcommand
   HKEY_CLASSES_ROOT xtfileshellprinttocommand
   HKEY_CLASSES_ROOTUnknownshellopenascommand
   HKEY_CLASSES_ROOT hemefileshellopencommand
   
   to change how the following actions are executed:
   
   
   • edit
   • open
   • print
     
     
8. Modifies the value:
   
   "(Default)" = "C:WINDOWSIpnuker.vbs"
   
   in the registry subkey:
   
   HKEY_CLASSES_ROOTShellshellexplorecommand
   
   so that worm runs when Windows Explorer starts.
   
   
9. Modifies the value by adding one of the following:
   
   "RegisteredOwner" = "Ipnuker.Net"
   "RegisteredOwner" = "Ipnuker"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersion
   
   to reset the registered owner.
   
   
10. Modifies the value by adding one of the following:
    
    "Start_Page" = "c:WINDOWSIpnuker.vbs"
    "Start_Page" = "http://]www.ipnuker.com/[REMOVED]"
    
    in the registry subkey:
    
    HKEY_LOCAL_MACHINESOFTWAREMicrosoftInternet ExplorerMain
    
    to redirect the Internet Explorer home page.
    
    
11. Attempts to spread via mIRC by creating a VBS file attachment. It does this by looking for the folders C:Mirc, C:Mirc32 and for the file, mirc.ini in those folders. If the file is found, the worm will either create or overwrite the script.ini file.
    
    Note: The worm never writes the vbs file to be sent.
    
    
12. May modify autoexec.bat. to read:
    
    @echo off
    echo This Computer Was Made By [REMOVED]
    echo Copyrighted By [REMOVED] For Forever
    pause>nul
    
    
13. Searches files with the extensions .vbs, .bat, .txt, .vbe or .ini. If these file types are found, the worm overwrites the file with a copy of itself.
    
    
14. Uses MAPI commands to send itself to all addresses in the Microsoft Outlook address book. The email has the following characteristics:
    
    
    • If the date is the 1st through the 14th of January, June or December:
      
      Subject: Important Windows Security Update
      Message: Open the attachment to begin the windows update. This update is very important to ensure your safety. Microsoft
      Attachment: Ipnuker.vbs
      
      
    • If the date is the 15th through the last day of January, June or December:
      
      Subject: Yo Wats Up There
      Message: Open the attached file to get to the pictures you wanted.
      Attachment: Ipnuker.vbs
      
      
15. Creates a random network user name when one of the following batch files is executed:
    
    
    • %Windir%IpUserCreate.bat
    • %Windir%IpUser.bat

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. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan and delete all the files detected.
4. Delete any values added to the registry.
5. Reset the changed icons.
   

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

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• How to disable or enable Windows Me System Restore
• How to turn off or turn on Windows XP System Restore

Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).

2. To update 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 Virus Definitions (LiveUpdate).
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. 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 Virus Definitions (Intelligent Updater).
  
  The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

3. To scan for and delete 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, click Delete.

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 threat 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.


4. 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. For instructions refer to the document: How to make a backup of the Windows registry.

1. Click Start > Run.
2. Type regedit
3. Click OK.
   
   Note: If the registry editor fails to open the threat 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.
   
   
4. Navigate to the subkey:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
5. In the right pane, delete the values:
   
   "WindosXp" = "Wscript.exe [SCRIPT NAME]"
   "DisableKeyboard" = "Rundll32.exe Keyboard,Disable"
   "DisableMouse" = "Rundll32.exe Mouse,Disable"
   
   
6. Navigate to the subkey:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionPoliciesExplorer
   
   
7. In the right pane, delete the value:
   
   "NoDesktop" = "1"
   
   
8. Navigate to the subkeys:
   
   HKEY_CLASSES_ROOT xtfileshellopencommand
   
   
9. In the right pane, reset the following value:
   
   "(Default)" = "%System%System32WScript.exe"
   
   with the following value:
   
   "(Default)" = "%Windir% otepad.exe "%1""
   
   
10. Navigate to the subkeys:
    
    HKEY_CLASSES_ROOT xtfileshellprintcommand
    
    
11. In the right pane, reset the following value:
    
    "(Default)" = "%System%System32WScript.exe"
    
    with the following value:
    
    "(Default)" = "%System%system32NOTEPAD.EXE /p %1"
    
    
12. Navigate to the subkeys:
    
    HKEY_CLASSES_ROOT xtfileshellprinttocommand
    
    
13. In the right pane, reset the following value:
    
    "(Default)" = "%System%System32WScript.exe"
    
    with the following value:
    
    "(Default)" = "%System%system32 otepad.exe /pt "%1" "%2" "%3" "%4""
    
    
14. Navigate to the subkeys:
    
    HKEY_CLASSES_ROOTUnknownshellopenascommand
    
    
15. In the right pane, reset the following value:
    
    "(Default)" = "%System%System32WScript.exe"
    
    with the following value:
    
    "(Default)" = "%System%system32undll32.exe %System%system32shell32.dll,OpenAs_RunDLL %1"
    
    
16. Navigate to the subkeys:
    
    HKEY_CLASSES_ROOTVBSFileShellCommand
    HKEY_CLASSES_ROOTVBSFileEditCommand
    HKEY_CLASSES_ROOT hemefileshellopen
    
    
17. In the right pane, delete the value:
    
    "(Default)" = "%SystemRoot%System32WScript.exe"
    
    Note: You may have to reset your Windows desktop theme via the Control Panel.
    
    
18. Navigate to the subkey:
    
    HKEY_CLASSES_ROOTShellshellexplorecommand
    
    
19. In the right pane, reset the value:
    
    "(Default)" = "C:WINDOWSIpnuker.vbs"
    
    with the following value:
    
    "(Default)" = "%SystemRoot%Explorer.exe /e,/idlist,%I,%L"
    
    
20. Navigate to the subkey:
    
    HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersion
    
    
21. In the right pane, delete the values, if present:
    
    "RegisteredOwner" = "Ipnuker.Net"
    "RegisteredOwner" = "Ipnuker"
    
    and reset with the correct information.
    
    
22. Navigate to the subkey:
    
    HKEY_LOCAL_MACHINESOFTWAREMicrosoftInternet ExplorerMain
    
    
23. In the right pane, delete the values, if present:
    
    "Start_Page" = "c:WINDOWSIpnuker.vbs"
    "Start_Page" = "[http://]www.ipnuker.com/[REMOVED]"
    
    
24. Exit the Registry Editor.
    
    

5. To reset the modified icons
You can reset changed icons by doing the following:

1. Click on My Computer
2. Click on Tools on the Menu bar.
3. Select Folder Options on the drop down menu.
4. Click on the File Types tab.
5. Select the application and press Advanced.
6. You will then have the option to change Icons.