Infostealer.Rivarts

1. Copies itself as %System%\zsys.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).
   
   
2. Adds the value:
   
   "Zsys" = "%System%\Zsys.exe"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   so that it runs every time Windows starts.
   
   
3. May add or modify registry entries in the following subkey to lower security settings:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
   
   
4. Creates the following files:
   
   
   • %Temp%\mc[RANDOM NAME].tmp
   • %System%\zsys1.dll
   • %System%\zsys2.dll
   • %Windir%\wscntfy.exe
     
     Note:
   • %Temp% is a variable that refers to the Windows temporary folder. By default, this is C:\Windows\TEMP (Windows 95/98/Me/XP) or C:\WINNT\Temp (Windows NT/2000).
   • %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).
     
     
5. Registers %Temp%\mc[RANDOM NAME].tmp as a Windows service by creating the following registry key:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\mchInjDrv
   
   
6. Inject the file ZSYS1.dll into every running process. The library is a malicious user-mode rootkit component that hooks the following Windows API to hide every file, process or registry key that contains the string zsys:
   
   
   • FindNextFileA
   • FindNextFileW
   • RegEnumValueA
   • RegEnumValueW
   • NtQuerySystemInformation
     
     
7. Redirects and hijacks browser traffic by hooking the following API using the user-mode rootkit component DLL:
   
   HttpSendRequestA
   
   
8. Using the user-mode rootkit component DLL, attempts to export and steal the web certificate store of the machine, using the password goblin by hooking the following API used during encrypted SSL communcation:
   
   PFXImportCertStore
   
   
9. Hooks the GetWindowTextA API and tries to steal web certificates when the user open the Internet Explorer window that has the title Select Certificate, using the user-mode rootkit component DLL.
   
   
10. Hooks the CreateFileW API and attempts to steal every file that contains the following string, using the user-mode rootkit component DLL:
    
    
    • NPKI (Nested certificate based PKI)
    • .key
    • .der
      
      
11. Steals sensitive information from Internet Explorer forms. It gathers information regarding the compromised computer configuration and the current operating system.
    
    
12. Creates the following log file in SQL language format to store part of the gathered information:
    
    %System%\zsys2.db
    
    
13. Attempts to contact the following Web sites to confirm its activity and to send the gathered information:
    
    
    • [http://]janes.ktuno.com/[PHP PAGE]
    • [http://]rusta.korpdate.com/[PHP PAGE]
    • [http://]rurik.medaus.net/[PHP PAGE]
    • [http://]robux.goodfriendszone.com/[PHP PAGE]
    • [http://]zitano.capitalizmu.net/[PHP PAGE]
    • [http://]frozen.devedent.com/[PHP PAGE]
      
      Where [PHP PAGE] is one of the following pages:
      
      
    • ping10[NUMBER].php
    • task10[NUMBER].php
    • storage10[NUMBER].php
      
      
14. May download and execute an updated version of itself from a remote site that can be configured by the attacker.
    
    
15. Opens a back door on a random TCP port.

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.