VBS.Yeno.C@mm

SUMMARY

VBS.Yeno.C@mm is a mass-mailing worm that sends itself to the email addresses in the Microsoft Outlook address book. It also infects .vbs, .vbe, .htm, and .html files on drives C, D and E.

Protection

• Virus Definitions (LiveUpdate™ Weekly) November 3, 2004
• Virus Definitions (Intelligent Updater) November 2, 2004

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
• Large Scale E-mailing: Sends email to all addresses in the Outlook address book.

Distribution

• Distribution Level: High
• Subject of Email: Fw: I give you again
• Name of Attachment: OXNEY.C.VBS

TECHNICAL DETAILS

When VBS.Yeno.C@mm runs, it does the following:

1. Sets the archive, system, and hidden attributes on the executed file.
   
   
2. Copies itself to %System%OXNEY.C.VBS.
   
   Note: %System% is a variable that refers to the System folder. By default, this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
   
   
3. Adds the following registry key:
   
   HKEY_USERS.DEFAULTSoftwareMicrosoftWindowsCurrentVersionSPINX
   
   
4. Adds the value:
   
   "SPINX" = "Wscript.exe %System%OXNEY.B.VBS %"
   
   to the registry key:
   
   HKEY_USERS.DEFAULTSoftwareMicrosoftWindowsCurrentVersionRun
   
   so that VBS.Yeno.C@mm runs every time Windows starts.
   
   
5. Adds the value:
   
   "Load-Guard" = "Wscript.exe %Windir%LGuarg.exe.vbs %"
   
   to the registry key:
   
   HKEY_USERS.DEFAULTSoftwareMicrosoftWindowsCurrentVersion
   RunServices
   
   so that VBS.Yeno.C@mm runs every time Windows starts.
   
   
6. Adds the value:
   
   "GeneralTab" = "1"
   
   to the registry key:
   
   HKEY_USERS.DEFAULTSoftwarePoliciesMicrosoftInternet ExplorerControl Panel
   
   so that VBS.Yeno.C@mm runs every time Windows starts.
   
   
7. Adds the values:
   
   "Window Title" = "Micosoft Internet Explorer Provided by : Spidey"
   "Start Page" = "Spidey.uni.cc"
   
   to the registry key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftInternet ExplorerMain
   
   so that VBS.Yeno.C@mm runs every time Windows starts.
   
   
8. Copies itself as the following file, if the current system time has a second value of 2:
   
   A:I am sorry.txt.vbs
   
   
9. Searches drives C, D, and E and infects files with .htm and .html extensions. The worm adds a script into the files it finds, which runs the following files:
   
   • %System%OXNEY.B.VBS
   • %Windir%LGuarg.exe.vbs
     
     Notes:
   • The worm does not create this file.
   • %Windir% is a variable that refers to the Windows installation folder. By default, this is C:Windows or C:Winnt.
     
     
10. Searches drives C, D, and E for files with .vbs, and .vbe extensions and infects them by appending a copy of itself.
    
    
11. Uses Microsoft Outlook to send an email to all addresses in the Outlook address book.
    
    The email has the following characteristics:
    
    Subject: 
    Fw: I give you again
    
    Message Body:
    Spidey has give you some password of xxx site
    (cute) Spidey
    
    Attachment:
    OXNEY.C.VBS
    

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 as VBS.Yeno.C@mm.
4. Delete the value that was added to the registry.
5. Reset the Internet Explorer home page.
   

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, re-enable 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 the 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 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.

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 as infected with VBS.Yeno.C@mm, click Delete.
   
   
   Note: If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix 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, you can leave the computer in Safe mode and proceed with section 4. When that is done, restart the computer in Normal mode.)
   

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 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 the key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
4. In the right pane, delete the value:
   
   "SPINX" = "Wscript.exe %System%OXNEY.C.VBS %"
   
   
5. Navigate to the key:
   
   HKEY_USERS.DEFAULTSoftwareMicrosoftWindowsCurrentVersion
   RunServices
   
   
6. In the right pane, delete the value:
   
   "Load-Guard" = "Wscript.exe %Windir%LGuarg.exe.vbs %"
   
   
7. Delete the following key:
   
   HKEY_USERS.DEFAULTSoftwareMicrosoftWindowsCurrentVersionSPINX
   
   
8. Exit the Registry Editor.
   
   

5. To reset the Internet Explorer home page

1. Start Microsoft Internet Explorer.
2. Connect to the Internet, and then 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.

For additional information, or if this procedure does not work, read the Microsoft® Knowledge Base article, "Home Page Setting Changes Unexpectedly, or You Cannot Change Your Home Page Setting, Article ID 320159."