Backdoor.Trodal

Due to bugs in Backdoor.Trodal's code, it will not run under Windows 95, Windows 98, or Windows Me.

Backdoor.Trodal is being uploaded to unpatched Windows Servers, using various vulnerabilities.

Once Backdoor.Trodal is activated, it does the following:

1. Creates the value:
   
    "[CompID]"="<string with nine random letters>"
   
   in the registry key:
   
   HKEY_CURRENT_USER\Software\Microsoft
   
   
2. Copies itself to %Windir%\Winlogon.exe.
   
   

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   Note: %Windir% is a variable. The Trojan locates the Windows installation folder (by default, this is C:\Windows or C:\Winnt) and copies itself to that location.

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3. Creates the registry value
   
   "winlogon"="%windir%\winlogon.exe"
   
   under the registry keys:
   
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunServices
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   so that the Trojan runs when you start Windows.
   
   
4. Sets the file timestamp of %Windir%\Winlogon.exe to the same values as the file, %Windir%\win.ini.
   
   
5. Downloads and executes various executables from a specified Web site.
   
   

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   Note: The executables that it downloads are freeware, password recovery utilities exploited to obtain information from your computer. They are saved as %Windir%\Dfp.exe and %Windir%\Pspv.exe. These programs are not malicious, and thus, Symantec antivirus programs do not detect them.
   

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   These executables collect various user information and stores them in these files:
   
   %Windir%\Windows.ini
   %Windir%\Windows2.ini
   
   The information that it collects include the following:
   
   • User dialup information (including passwords)
   • Various cached passwords stored on the system, including:
     • Saved Microsoft Outlook passwords
     • Saved MSN passwords
   • User account name
   • User name
   • All information stored in the registry key:
     
     HKEY_LOCAL_MACHINE\SOFTWARE\WebMoney\Options
     
     
6. Searches all the local hard drives and steals information from these files:
   
   • Fethard_keyfile
   • Userpref.ini
   • Ipass.ini
   • Wcx_ftp.ini
   • Edialer.ini
   • Ws_ftp.ini
   • Pal.ini
   • Pal95.ini
   • Any files with the extensions, .pwm, .kwm, or .uin
     
     
7. Sends the stolen information to email addresses in Russia and Slovenia.
   
   
8. Creates several threads that never exit:
   • Thread 1
     Contacts an irc server and joins an irc channel where it waits for the recognized commands:
     • !run (Executes a command on the system).
     • !rec (Reconnects the backdoor to irc).
     • !mai (Sends data collected in the files Windows.ini and Windows2.ini using email).
     • !inf (Iterates through the system, stealing various information).
     • !ext (Shuts down the computer).
     • !ver (Sends various version information about the system and the Trojan).
       
       
   • Thread 2
     Contacts a remote server and notifies that it exists on a compromised system, repeating this every 11 minutes.
     
     
   • Thread 3
     Creates a Web server on a random port, in the range 1000-15000, which allows a remote attacker to use a compromised system as a proxy for Web traffic.

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.

Summary