W32.Korgo.Q

1. Deletes the file ftpupd.exe from the folder where the worm is executed.
   
   
2. Creates the mutex "uterm15" to ensure that only one instance of the worm can run on a computer at any time.
   
   
3. Deletes the following entries:
   
   "Windows Security Manager"
   "Disk Defragmenter"
   "System Restore Service"
   "Bot Loader"
   "SysTray"
   "WinUpdate"
   "Windows Update Service"
   "avserve.exe"
   "avserve2.exeUpdate Service"
   "MS Config v13"
   
   from the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   
4. Attempts to terminate the processes associated with the registry entries mentioned above.
   
   
5. Copies itself to %System% folder using a random file name (5 to 8 lower case letters) with a .exe extension.
   
   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).
   
   
6. Adds the values:
   
   "Client"
   "ID"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Wireless
   
   
7. Adds the value:
   
   "Windows Update"="%System%\[random name].exe"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   
8. Attempts to inject a function as a thread into processes with a window class name of "Shell_TrayWnd" or into the process running in the foreground.
   
   If successful, this threat will continue to run within the infected process. All of the following actions will appear to be done by the infected process, and the worm will stop its own process.
   
   If unsuccessful, it will continue to run as its own process.
   
   
9. Makes an HTTP request to one of the following servers:
   
   
   • mazafaka.ru
   • xware.cjb.net
   • citi-bank.ru
   • konfiskat.org
   • adult-empire.com
   • parex-bank.ru
   • kidos-bank.ru
   • crutop.nu
   • kavkaz.ru
   • color-bank.ru
   • master-x.com
   • asechka.ru
   • trojan.ru
   • padonki.org
   • fuck.ru
   • goldensand.ru
   • filesearch.ru
   • lovingod.host.sk
   • www.redline.ru
   • cvv.ru
   • hackers.lv
   • fethard.biz
     
     The worm reads a certain file from these sites. If the file does not contain the string "zer0", the worm will wait and reconnect in the same way. This will continue until the file contains the string "zer0". In this case, the worm downloads a file from the website to the %System% folder and executes it. The worm must authenticate to the Web site before downloading the file.
     
     
10. Opens a random port between 2000 and 8191, which the worm uses to send itself.
    
    
11. Attempts to exploit the LSASS Windows vulnerability on TCP port 445 (described in Microsoft Security Bulletin MS04-011), against random IP addresses. If the worm successfully finds a vulnerable computer, the computer will attempt to reconnect to the infected computer to download the worm.

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.