1. Symantec/
  2. Security Response/
  3. BackOrifice2K.Trojan


Risk Level 1: Very Low

July 11, 1999
February 13, 2007 11:58:22 AM
Trojan Horse

Technical Notes

The server application may be configured with several different options. The networking protocol may be TCP or UDP. Any port number between 1 and 65535 may be selected for communication.

In the US version, the information transmitted may be encrypted by XOR or using 3DES. The 3DES encryption is not available in the international version.

The encryption key is programmable for both types of encryption. When the server program is executed for the first time on a system, it may copy itself to the \WINDOWS\SYSTEM directory on a Windows 9x system, and the \WINNT\SYSTEM32 directory on a Windows NT system. After being copied to the Windows system directory, the program may delete the original copy of itself. The name of the copied file is programmable. The default name of the copied executable begins with UMGR32. The server program may be configured to start itself upon Windows startup by adding an entry to the registry.

The program may also be set to hide itself from a process viewer such as Task Manager in Windows NT. If it is not hidden, the process name may be any name because it is also configurable. Plug-ins to this program may be integrated to add new functionality.

The following is a list of commands the client program may send to the server program:

  • Ping and query the server
  • Reboot or lock up the system
  • List cached and screen saver passwords
  • Display system information
  • Log keystrokes, view the keystroke log and delete the keystroke log
  • Display a message box
  • Map a port to another IP address, application, HTTP file server, or filename
  • List ports mapped by BackOrifice 2000
  • Send a file through another port
  • Share a drive, unshare a drive, list shared drives, list shared devices on a LAN, mapped a shared device, unmap a shared device and list all connections
  • List current processes, kill a process and start a process
  • View and edit the registry - create a key, set a value, get a value, delete a key, delete a value, rename a key, rename a value, enumerate keys and enumerate values
  • Video and audio capture and playback
  • Capture a screen shot
  • File and directory commands - list directory, find file, delete file, view file, move file, rename file, copy file, make directory, remove directory and set file attributes
  • Receive and send files
  • Compress and uncompress files
  • Resolve host name and address
  • Server control - shutdown server, restart server, load plug-in, remove plug-in and list plug-ins


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.
Writeup By: Raul Elnitiarta
Summary| Technical Details| Removal

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