Backdoor.Beasty.F

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Discovered: March 31, 2003
Updated: February 13, 2007 11:45:11 AM
Also Known As: Backdoor.Beastdoor.192.g [KAV], BackDoor-AMQ [McAfee]
Type: Trojan Horse
Systems Affected: Windows


The Backdoor.Beasty.F Trojan opens a listening port (TCP 23666) on your computer. This action may allow a hacker to remotely control your computer.

Backdoor.Beasty.F uses web.icq.com to send a message to the hacker's ICQ Unified Messaging Center. This message includes the IP address of the infected computer.

This threat is written in the Borland Delphi programming language.

Antivirus Protection Dates

  • Initial Rapid Release version March 31, 2003
  • Latest Rapid Release version March 03, 2008 revision 035
  • Initial Daily Certified version March 31, 2003
  • Latest Daily Certified version March 03, 2008 revision 037
  • Initial Weekly Certified release date April 02, 2003

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Yana Liu

Discovered: March 31, 2003
Updated: February 13, 2007 11:45:11 AM
Also Known As: Backdoor.Beastdoor.192.g [KAV], BackDoor-AMQ [McAfee]
Type: Trojan Horse
Systems Affected: Windows


When Backdoor.Beasty.F runs, it does the following:

  1. Copies itself as these files:
    • %System%\Explorer.exe
    • %System%\Shell32.pif, whose attribute is set to Hidden
    • %System%\Wbem\Wb.com, whose attribute is set to Hidden
    • %System%\Com\Mscom32.com, whose attribute is set to Hidden

      NOTE: %System% is a variable. The Trojan locates the System folder and creates folders 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).

  2. Adds the value:

    COM Service %System%\COM\mscom32.com

    to the registry key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

    so that the worm runs when you start Windows.
  3. Creates the registry key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components\
    {45DD0432-AA51-31EF-EEFA-06AA12E6115C}

    and adds the following value to this key:

    StubPath %System%\wbem\wb.com
  4. Modifies the (default) values of the registry keys:

    HKEY_CLASSES_ROOT\comfile\shell\open\command
    HKEY_CLASSES_ROOT\exefile\shell\open\command
    HKEY_CLASSES_ROOT\piffile\shell\open\command

    to:

    (Default) shell32.pif"%1"%*

    so that the Trojan is executed each time you execute a .com, .exe, or .pif file.
  5. Emails the name and IP address of the infected computer to the hacker.
  6. Notifies the hacker through ICQ.
  7. Listens on TCP port 23666 and waits for the commands from the hacker.


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.

Writeup By: Yana Liu

Discovered: March 31, 2003
Updated: February 13, 2007 11:45:11 AM
Also Known As: Backdoor.Beastdoor.192.g [KAV], BackDoor-AMQ [McAfee]
Type: Trojan Horse
Systems Affected: Windows



The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

NOTES:

  • If the Trojan has not yet run—that is, the Trojan's file was copied to your computer but has not run—you should be able to follow the instructions in sections 1 and 2, which discuss detecting and removing this file. (If the Trojan has run, in most cases you will not be able to follow these instructions, as the modifications that the worm made will prevent you from doing so.)
  • If the Trojan has run, or if you are not sure, first follow the instructions in section 3. After completing those instructions, follow the steps in sections 1 and 2.
  1. Update the virus definitions.
  2. Run a full system scan and delete all the files detected as Backdoor.Beasty.F.
  3. Reverse the changes made to the registry.
For specific details on each of these steps, read the following instructions.

1. Updating the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).

    The Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

2. Scanning for and deleting the infected files
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected as infected with Backdoor.Beasty.F, click Delete.

3. Reversing the changes made to the registry
If the Trojan has already executed, it may have modified the registry so that the Trojan is executed each time you execute a .com, .exe, or .pif file.
To avoid this, first make a copy of the Registry Editor as a file with the .scr extension, and then run that particular file.
  1. Restart the computer in Safe mode. All the Windows 32-bit operating systems, except Windows NT, can be restarted in Safe mode. For instructions on how to do this, read the document, "How to start the computer in Safe Mode."
  2. Depending on the version of Windows you are running, do one of the following:
    • Windows 95/98 users:
      1. Click Start.
      2. Point to Programs.
      3. Click the MS-DOS Prompt. (A DOS window opens at the C:\Windows prompt.) Proceed to step c of this section.
    • Windows Me users:
      1. Click Start.
      2. Point to Programs.
      3. Point to Accessories.
      4. Click the MS-DOS Prompt. (A DOS window opens at the C:\Windows prompt.) Proceed to step c of this section.
    • Windows NT/2000 users:
      1. Click Start, and then click Run.
      2. Type command, and then press Enter. (A DOS window opens.)
      3. Type cd \winnt, and then press Enter.
      4. Go to step c of this section.
    • Windows XP users:
      1. Click Start, and then click Run.
      2. Type command, and then press Enter. (A DOS window opens.)
      3. Type the following:

        cd\
        cd \windows

        Press Enter after typing each one.
      4. Proceed to step c of this section.

  3. Type copy regedit.exe regedit.scr

    and then press Enter.
  4. Type start regedit.scr

    and then press Enter. (The Registry Editor opens in front of the DOS window.)

    After you finish editing the registry, exit the Registry Editor, and then exit the DOS window as well.
  5. Before continuing, Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. For instructions, read the document, "How to make a backup of the Windows registry."
  6. Navigate to and select the key:

    HKEY_CLASSES_ROOT\exefile\shell\open\command

    NOTE: The HKEY_LOCAL_MACHINE\Software\Classes key contains many subkey entries that refer to other file extensions. One of these file extensions is .exe. Changing this extension can prevent any files ending with a .exe extension from running. Make sure that you completely browse through this path until you reach the \command subkey.

    Modify the HKEY_CLASSES_ROOT\exefile\shell\open\command subkey, shown in the following figure:

    <<=== NOTE: Modify this key.
  7. In the right pane, double-click the (Default) value.
  8. Delete the current value data, and then type:

    "%1" %*

    That is, type the characters: quote-percent-one-quote-space-percent-asterisk.

    NOTES
    • Under Windows 95/98/Me/NT, the Registry Editor automatically encloses the value within quotation marks. When you click OK, the (Default) value should look exactly like this:

      ""%1" %*"  
    • Under Windows 2000/XP, the additional quotation marks will not appear. When you click OK, the (Default) value should look exactly like this:

      "%1" %*
    • Make sure that you completely delete all the value data in the command key before typing the correct data. If you leave a space at the beginning of the entry, any attempt to run the program files will result in the error message, "Windows cannot find .exe." If this occurs, restart the entire process from the beginning of this section, and make sure that you completely remove the current value data.

  9. Navigate to the key:

    HKEY_CLASSES_ROOT\comfile\shell\open\command
  10. Repeat the procedure described in steps g and h.
  11. Navigate to the key:

    HKEY_CLASSES_ROOT\piffile\shell\open\command

    Repeat the procedure described in steps g and h.
  12. Navigate to the key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  13. In the right pane, delete the value:

    COM Service %System%\COM\mscom32.com
  14. Navigate to the key and delete it:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components\
    {45DD0432-AA51-31EF-EEFA-06AA12E6115C}
  15. Exit the Registry Editor.
  16. Restart the computer and follow the instructions in sections 1 and 2.


Writeup By: Yana Liu