Trojan.Gletta.A

1. Copies itself to:
   • %System%\Wmiprvse.exe
   • %System%\Ntsvc.exe
   • %Windir%\Userlogon.exe
     
     

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     Notes:
     %System% is a variable. Trojan.Gletta.A locates the System folder and copies itself to that location. By default, this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
     
     %Windir% is a variable. The Trojan.Gletta.A locates the Windows installation folder (by default, this is C:\Windows or C:\Winnt) and copies itself to that location.

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2. Creates the file, %System%\Rsasec.dll, which is a keylogger.
   
   
3. Creates the file, %System%\rsacb.dll, which is actually a text file.
   
   
4. Adds the value:
   
   "wmiprvse.exe"="%system%\wmiprvse.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   so that the Trojan runs when you start Windows.
   
   
5. On Windows NT/2000/XP, it adds the value:
   
   "Run" = "%Windir%\userlogon.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows
   
   so that the Trojan runs when you start these operating systems.
   
   
6. On Windows 95/98/Me, it adds the line:
   
   run=%Windir%\userlogon.exe
   
   to the Win.ini file so that the Trojan runs when you start these operating systems.
   
   
7. On Windows 95/98/Me, it changes the shell= line to:
   
   shell=explorer.exe %system%\ntsvc.exe
   
   so that the Trojan runs when you start these operating systems.
   
   
8. Watches for Internet Explorer windows that have any of the following titles:
   
   National Australia Bank
   ANZ Internet Banking - Logon
   National Internet Banking
   Citibank Australia
   Welcome to Citi
   Welcome to Citibank
   Citi - Sign On
   Bank of China
   online@hsbc
   HSBC in Hong Kong
   Banesto
   Sabadell
   
   or one of the following URLs:
   
   https:/ /olb.westpac.com.au/ib/asp/
   https:/ /olb.westpac.com.au/ib/
   
   
9. Captures all the keystrokes entered into any windows that match those listed above, and writes them into a log file.
   
   
10. Uses its own SMTP engine to send the log file to an external mail account. It uses an SMTP server in Russia to send the mail.
    
    The mail has the following characteristics:
    
    Both the FROM and TO addresses have the domain "mail.ru"
    The subject starts with "Business News from "
    

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.