W32.Bobax.AJ@mm

SUMMARY

W32.Bobax.AJ@mm is a mass-mailing worm that spreads by exploiting the Microsoft Windows Plug and Play Buffer Overflow Vulnerability (described in Microsoft Security Bulletin MS05-039) on TCP port 445. The worm allows a compromised computer to be used as a covert proxy.

Protection

• Virus Definitions (LiveUpdate™ Weekly) September 7, 2005
• Virus Definitions (Intelligent Updater) September 7, 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: Medium
• Payload: Downloads remote files.
• Deletes Files: Deletes %Temp%~* files.
• Degrades Performance: Exploits a remote vulnerability which may degrade performance.
• Causes System Instability: Attempts to use the compromised computer as a covert proxy.
• Compromises Security Settings: Compromises security settings by blocking access to security-related Web sites.

Distribution

• Distribution Level: High
• Subject of Email: Varies
• Name of Attachment: Varies
• Ports: TCP Port 445

TECHNICAL DETAILS

When W32.Bobax.AJ@mm is executed, it performs the following actions:

1. Copies itself as:
   
   %System%[RANDOM FILE NAME].exe.
   
   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).
   
   
2. Creates the following .dll file:
   
   %Temp%Was*.tmp
   
   Note: %Temp% is a variable that refers to the Windows temporary folder. By default, this is C:WindowsTEMP (Windows 95/98/Me/XP) or C:WINNTTemp (Windows NT/2000).
   
   
3. Injects the file %Temp%Was*.tmp into all processes that begin with the following strings:
   
   
   • expl
   • Winl
   • serv
     
     This includes the following Windows system processes:
     
     
   • explorer.exe
   • Winlogon.exe
   • services.exe
     
     
4. Downloads files to %Windir%[RANDOM STRING].tmp from the following URLs:
   
   
   • [http://]ftp.icq.com/[REMOVED]/icq4_setup.exe
   • [http://]ftp.scarlet.be/[REMOVED]/Firefox Setup 1.0.exe
   • [http://]ftp.newaol.com/[REMOVED]/Install_AIM.exe
     
     Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:Windows or C:Winnt.
     
     
5. Adds the value:
   
   "[RANDOM VALUE]" = "%System%[RANDOM FILE NAME].exe"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   so that it runs every time Windows starts.
   
   
6. Adds the value:
   
   "Start" = "4"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesSharedAccess
   
   to disable SharedAccess service in Windows XP/2000.
   
   
7. Modifies the values:
   
   "AntiVirusDisableNotify" = "1"
   "AntiVirusOverride" = "1"
   "FirewallDisableNotify" = "1"
   "FirewallOverride" = "1"
   "UpdatesDisableNotify" = "1"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftSecurity Center
   
   to lower security settings.
   
   
8. Disables the Windows firewall.
   
   
9. Deletes the following files:
   
   %Temp%~*
   
   
10. Attempts to use the compromised computer as a covert proxy.
    
    
11. Retrieves email addresses from files with the following extensions:
    
    
    • .HTM
    • .TXT
    • .DBX
      
      
12. Retrieves email addresses from the Windows Address Book and the Windows Messenger contact list.
    
    
13. Sends a copy of itself to the email addresses gathered using one of the following SMTP servers :
    
    
    • mailin-01.mx.aol.com
    • mailin-02.mx.aol.com
    • mailin-03.mx.aol.com
    • mailin-04.mx.aol.com
    • mx1.hotmail.com
    • maila.microsoft.com
      
      The email may have the following characteristics:
      
      Subject:
      One of the following:
      
      
    • pics
    • funny
    • bush
    • joke
    • secret
      
      Message:
      One of the following:
      
      
    • Saddam Hussein - Attempted Escape, Shot dead
      Attached some pics that i found
      
      
    • Osama Bin Laden Captured.
      Attached some pics that i found
      
      
    • Testing
      
      
    • Secret!
      
      
    • Hey,
      Remember this?
      
      
    • Hello,
      Long time! Check this out!
      
      
    • Hey,
      I was going through my album, and look what I found..
      
      
    • Hey,
      Check this out :-)
      
      Followed by one of the following:
      
      
    • ++ Attachment: No Virus found
      ++ Panda AntiVirus - You are protected
      ++ www.pandasoftware.com
      
      
    • ++ Attachment: No Virus found
      ++ Norman AntiVirus - You are protected
      ++ www.norman.com
      
      
    • ++ Attachment: No Virus found
      ++ F-Secure AntiVirus - You are protected
      ++ www.f-secure.com
      
      
    • ++ Attachment: No Virus found
      ++ Norton AntiVirus - You are protected
      +++ www.symantec.com
      
      Attachment:
      One of the following:
      
      
    • pics
    • funny
    • bush
    • joke
    • secret
      
      with one of the following extensions:
      
      
    • .pif
    • .scr
    • .exe
    • .zip
      
      Avoids sending itself to email addresses whose domain contains any of the following strings:
      
      
    • ogle
    • help
    • admi
    • ter@
    • micr
    • supp
    • yman
    • viru
    • tren
    • secu
    • .mil
    • urhq
    • pand
    • afee
    • soph
    • kasp
    • .gov
    • nort
      
      
14. Scans randomly generated IP addresses, and attempts to exploit the Microsoft Windows Plug and Play Buffer Overflow Vulnerability (described in Microsoft Security Bulletin MS05-039) on TCP port 445.
    
    
15. Downloads and executes an executable file on the newly compromised computer. This file is then saved with a .gif extension.
    
    
16. Infects files referenced in the following registry subkey:
    
    HKEY_LOCAL_MACHINESofwareMicrosoftWindowsCurrentVersionRun subkey
    
    
17. Contacts one of the following domains on a remote Web server and sends a unique ID and information about the newly compromised computer as notification of infection:
    
    
    • 2mydns.net
    • widescreenhd.tv
    • mycoding.com
    • a.la
    • mario.org
    • mykgb.com
    • systes.net
    • zipitover.com
      
      
18. Searches for and infects .exe files.
    
    
19. Renames files it copies to the compromised computer by appending .tmp to the filename and extension.
    
    Note: The worm would rename example.exe to example.exe.tmp
    
    
20. Adds the following text to the hosts file to block access to several security-related Web sites:
    
    255.255.255.255
    ar.atwola.com
    atdmt.com
    avp.ch
    avp.com
    avp.ru
    awaps.net
    ca.com
    dispatch.mcafee.com
    download.mcafee.com
    download.microsoft.com
    downloads.microsoft.com
    engine.awaps.net
    f-secure.com
    ftp.f-secure.com
    ftp.sophos.com
    go.microsoft.com
    liveupdate.symantec.com
    mast.mcafee.com
    mcafee.com
    msdn.microsoft.com
    my-etrust.com
    nai.com
    networkassociates.com
    office.microsoft.com
    phx.corporate-ir.net
    secure.nai.com
    securityresponse.symantec.com
    service1.symantec.com
    sophos.com
    spd.atdmt.com
    support.microsoft.com
    symantec.com
    update.symantec.com
    updates.symantec.com
    us.mcafee.com
    vil.nai.com
    viruslist.ru
    windowsupdate.microsoft.com
    www.avp.ch
    www.avp.com
    www.avp.ru
    www.awaps.net
    www.ca.com
    www.f-secure.com
    www.kaspersky.ru
    www.mcafee.com
    www.my-etrust.com
    www.nai.com
    www.networkassociates.com
    www.sophos.com
    www.symantec.com
    www.trendmicro.com
    www.viruslist.com
    www.viruslist.ru
    www3.ca.com

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. Remove all the entries that the risk added to the hosts file.
3. Update the virus definitions.
4. Run a full system scan and delete all the files detected.
5. Delete any values added to the registry.
   

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).

To remove all the entries that the risk added to the hosts file

1. Navigate to the following location:
   
   
   • Windows 95/98/Me:
     %Windir%
   • Windows NT/2000/XP:
     %Windir%System32driversetc
     
     Notes:
   • The location of the hosts file may vary and some computers may not have this file. There may also be multiple copies of this file in different locations. If the file is not located in these folders, search your disk drives for the hosts file, and then complete the following steps for each instance found.
   • %Windir% is a variable that refers to the Windows installation folder. By default, this is C:Windows (Windows 95/98/Me/XP) or C:Winnt (Windows NT/2000).
     
     
2. Double-click the hosts file.
3. If necessary, deselect the "Always use this program to open this program" check box.
4. Scroll through the list of programs and double-click Notepad.
5. When the file opens, delete all the entries added by the risk. (See the Technical Details section for a complete list of entries.)
6. Close Notepad and save your changes when prompted.

3. 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.

4. 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.


5. 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 value:
   
   "[RANDOM VALUE]" = "%System%[RANDOM FILE NAME].exe"
   
   
6. Exit the Registry Editor.