Backdoor.Nibu.O

1. Copies itself as %System%\winldra.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. Creates the following files:
   
   
   • %Windir%\dvpd.dll
   • %Windir%\prntsvra.dll
   • %Windir%\winsms.dll
   • %Windir%\TEMP\fe43e701.htm
     
     Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.
     
     
3. Adds the value:
   
   "load32" = "%System%\winldra.exe"
   
   to the following registry subkey
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   so that it runs every time Windows starts.
   
   
4. Creates the following registry subkey to store configuration information:
   
   HKEY_CURRENT_USER\SOFTWARE\SARS
   
   
5. Attempts to hide its presence on the compromised computer from Windows Task Manager.
   
   
6. Sends information about the compromised computer to the following Web sites:
   
   
   • [http://]www.wlm.at/[REMOVED]/logger.php
   • [http://]www.wlm.at/[REMOVED]/socks.php
     
     
7. Sets the values:
   
   "Append Completion" = "yes"
   "AutoSuggest" = "yes
   
   in the registry subkey:
   
   HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
   Explorer\AutoComplete
   
   to modify the behavior of Internet Explorer.
   
   
8. Sets the value:
   
   "Start" = "3"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SharedAccess
   
   to disable the Windows firewall.
   
   
9. Captures keystrokes typed into those browser windows where the window titles contain one of the following strings:
   
   
   • anz
   • ANZ
   • Bank
   • bank
   • bet
   • Bet
   • bill
   • Bill
   • bookmak
   • Bookmak
   • bull
   • Bull
   • cash
   • casino
   • Casino
   • ebay
   • e-metal
   • Fethard
   • fethard
   • fund
   • Fund
   • gold
   • invest
   • Invest
   • Keeper
   • login
   • Login
   • member
   • Member
   • Money
   • money
   • mull
   • pay
   • Pay
   • PayPal
   • shop
   • Shop
   • Storm
   • TAN
   • WM Keeper
     
     
10. Monitors Internet Explorer for data submitted in Web forms and logs this information in one of the following files:
    
    
    • %Windir%\netdx.dat
    • %Windir%\cmdid.dat
    • %Windir%\socks.dat
    • %Windir%\prntk.log
    • %Windir%\url.dat
      
      
11. Attempts to steal the following types of information:
    
    
    • FAR Manager passwords
    • FTP Commander passwords
    • Bat email passwords
    • Protected storage data
    • IP address of the infected computer
    • Operating system version
    • Internet Explorer version
      
      
12. Monitors the clipboard, and saves any data found into the following log file:
    
    %Windir%\prntc.log
    
    
13. Checks the size of the files it uses for logging stolen information. When the files reach a certain size, the stolen information is sent to a predetermined email address using the Trojan's own SMTP engine.
    
    
14. Opens a back door on TCP port 39780, and listens for further instructions from a remote attacker.
    
    
15. Adds the following text to the hosts file, blocking access to several security-related Web sites:
    
    127.0.0.1  www.trendmicro.com
    127.0.0.1  trendmicro.com
    127.0.0.1  rads.mcafee.com
    127.0.0.1  customer.symantec.com
    127.0.0.1  liveupdate.symantec.com
    127.0.0.1  us.mcafee.com
    127.0.0.1  updates.symantec.com
    127.0.0.1  update.symantec.com
    127.0.0.1  www.nai.com
    127.0.0.1  nai.com
    127.0.0.1  secure.nai.com
    127.0.0.1  dispatch.mcafee.com
    127.0.0.1  download.mcafee.com
    127.0.0.1  www.my-etrust.com
    127.0.0.1  my-etrust.com
    127.0.0.1  mast.mcafee.com
    127.0.0.1  ca.com
    127.0.0.1  www.ca.com
    127.0.0.1  networkassociates.com
    127.0.0.1  www.networkassociates.com
    127.0.0.1  avp.com
    127.0.0.1  www.kaspersky.com
    127.0.0.1  www.avp.com
    127.0.0.1  kaspersky.com
    127.0.0.1  www.f-secure.com
    127.0.0.1  f-secure.com
    127.0.0.1  viruslist.com
    127.0.0.1  www.viruslist.com
    127.0.0.1  liveupdate.symantecliveupdate.com
    127.0.0.1  mcafee.com
    127.0.0.1  www.mcafee.com
    127.0.0.1  sophos.com
    127.0.0.1  www.sophos.com
    127.0.0.1  symantec.com
    127.0.0.1  securityresponse.symantec.com
    127.0.0.1  us.mcafee.com/root/
    127.0.0.1  www.symantec.com

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.