W32.Zotob.G

1. Creates the mutex "windrg32", so that only one copy of the worm runs on the compromised computer at one time.
   
   
2. Copies itself as the following file:
   
   %System%\usrnt\windrg32.exe
   
   Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
   
   
3. Deletes the original worm file.
   
   
4. Adds the value:
   
   "WinDrg32" = "%System%\usernt\windrg32.exe"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   so that it runs every time Windows starts.
   
   
5. Fails to operate correctly if it detects it is not connected to a network, if the computer's IP address is non-routable, or if it is unable to lookup www.google.com, www.ebay.com, or www.yahoo.com.
   
   
6. Attempts to open a back door by connecting to one of the following IRC servers on TCP port 6667 and joining the channel #xaeti:
   
   
   • spookestreet.afraid.org
   • spookystreet.udp-flood.com
   • sppokystreet.m00p.org
   • spookystreet.afraid.org
     
     Note: At the time of writing these servers were unavailable.
     
     
7. Allows the remote attacker to perform the following commands on the compromised computer:
   
   
   • Download and execute files
   • Send queries to www.google.com
   • End processes
   • Send random IRC messages
   • Check for email on [http://]www.mailinator.com/[REMOVED]
   • Submit URLs to [http://]tinyurl.com/[REMOVED]
     
     
8. Opens a TFTP server on UDP port 69.
   
   
9. Attempts to end the following processes:
   
   
   • CxtPls.exe
   • EbatesMoeMoneyMaker*.exe
   • CMESys.exe
   • qttask.exe
   • realsched.exe
   • ViewMgr.exe
   • NHUpdater.exe
     
     
10. Deletes the following registry values:
    
    "FunWebProducts"
    "MyWebSearch"
    "MyWay"
    "WeatherOnTray"
    "Hotbar"
    "sais"
    "msbb"
    "saie"
    "180ax"
    "lgbibsn"
    "tov"
    "180"
    "WinTools"
    "IBIS TB"
    "TBPS"
    "Toolbar"
    "Apropos"
    "NavExcel"
    "ViewMgr"
    "Viewpoint"
    "TkBellExe"
    "Real"
    "QuickTime Task"
    "QuickTime"
    "CMESys"
    "Gator"
    "Trickler"
    "GatorDownloader"
    "eZmmod"
    "eZula"
    "EbatesMoeMoneyMaker"
    "Ebates"
    "AutoUpdater"
    
    from the following subkeys:
    
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Run
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\RunOnce
    
    
11. Deletes the following files and deletes the contents of the following folders:
    
    
    • %ProgramFiles%\FunWebProducts
    • %ProgramFiles%\FunWebProducts\*.exe
    • %ProgramFiles%\MyWebSearch
    • %ProgramFiles%\MyWebSearch\*.exe
    • %ProgramFiles%\MyWay
    • %ProgramFiles%\MyWay\*.exe
    • %ProgramFiles%\Hotbar
    • %ProgramFiles%\Hotbar\*.exe
    • %ProgramFiles%\180Solutions
    • %ProgramFiles%\180Solutions\*.exe
    • %ProgramFiles%\Common Files\WinTools
    • %ProgramFiles%\Common Files\WinTools\*.exe
    • %ProgramFiles%\Toolbar
    • %ProgramFiles%\Toolbar\*.exe
    • %ProgramFiles%\CxtPls
    • %ProgramFiles%\NavExcel
    • %ProgramFiles%\Common Files\GMT
    • %ProgramFiles%\Common Files\GMT\GMT.exe
    • %ProgramFiles%\Common Files\CMEII
    • %ProgramFiles%\eZula
    • %ProgramFiles%\eZula\mmod.exe
    • %ProgramFiles%\EbatesMoeMoneyMaker
    • %ProgramFiles%\AutoUpdate
    • %ProgramFiles%\AutoUpdate\AutoUpdate.exe
      
      
12. Generates random IP addresses, and attempts to exploit the Microsoft Windows Plug and Play Buffer Overflow Vulnerability (described in Microsoft Security Bulletin MS05-039), using TCP port 445.
    
    
13. Sends a file to the target computer. This file contains a TFTP script that will download a copy of the worm from the compromised computer.
    
    
14. Saves this file as run[NUMBER].exe on the remote computer and executes it.
    
    Note: [NUMBER] represents several random numbers from 0 - 9.
    
    
15. Logs the successfully exploited IP addresses to the IRC server it joined.

Recommendations

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

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• 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.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. 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.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.