Backdoor.Beasty.B

SUMMARY

Backdoor.Beasty.B is a backdoor Trojan, which is similar to Backdoor.Beasty. Backdoor.Beasty.B gives a hacker complete access to the infected computer. By default, the Trojan listens on port 666 and notifies the hacker through email or ICQ. The Trojan attempts to terminate various security products and system monitoring tools.

The Backdoor.Beasty.B Trojan was created using Delphi.

Protection

• Virus Definitions (LiveUpdate™ Weekly) January 29, 2003
• Virus Definitions (Intelligent Updater) January 29, 2003

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Medium
• Releases Confidential Info: Sends name and IP address of infected computer to hacker.
• Compromises Security Settings: Terminates several security products and system monitoring tools.

Distribution

• Distribution Level: Low
• Ports: 666

TECHNICAL DETAILS

When Backdoor.Beasty.B is executed, it reads the configuration data from itself. Then, it performs some or all of the following actions:

1. Terminates several security products and system monitor tools.
   
2. Copies itself to the %System% folder as Mshost.exe.
   
   NOTE: %System% is a variable. The Trojan locates the System folder and copies itself to that location. By default, the location is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
   
3. Copies itself to the %System%WBEM folder as Wsv.com.
   
4. Creates the registry key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftActive Setup
   Installed Components{44AF0969-CC51-11CF-AAFA-06AA00F6115C}
   
   and adds the value:
   
   StubPath %system%WBEMwsv.com
   
   to this registry key. This causes the Trojan to run every time you start Windows.
   
5. Modifies the (Default) value of the registry key:
   
   HKEY_CLASS_ROOTexefileshellopencommand
   
   This causes the Trojan to execute every time a .exe file is executed.
   
6. Logs the keyboard events.
   
7. Emails the name and IP address of the infected computer to the hacker.
   
8. Notifies the hacker through ICQ.
   
9. Listens on port 666 and waits for a command from the hacker.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

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

1. Reverse the changes that the Trojan made to the registry, and then restart the computer.
2. Update the virus definitions.
3. Run a full system scan and delete all the files detected as Backdoor.Beasty.B.

For specific details on each of these procedures, read the following instructions.

1. Reversing the changes that the Trojan made to the registry

Because the Trojan modified the registry so that the Trojan runs when you run any .exe file, first make a copy of the Registry Editor as a file with the .com extension, and then run the copy. Then, edit the registry.

1. Do one of the following, depending on which version of Windows you are running:
   1. 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 2, "Updating the virus definitions," of this section.
   2. 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 2, "Updating the virus definitions," of this section.
   3. 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 2 of this section.
   4. 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 2 of this section.
         
2. Type copy regedit.exe regedit.com, and then press Enter.
   
3. Type start regedit.com, and then press Enter. (The Registry Editor will open in front of the DOS window.)
   
   After you finish editing the registry, exit the Registry Editor, and then exit the DOS window as well.
   
4. Before continuing, Symantec strongly recommends that you back up the registry before you make 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."
   
5. Navigate to and select the key:
   
   HKEY_CLASS_ROOTexefileshellopencommand
   
   NOTE: The HKEY_CLASS_ROOT 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 an .exe extension from running. Make sure that you completely browse throughout this path until you reach the command subkey.
   
   Modify the HKEY_CLASS_ROOTexefileshellopencommand subkey, shown in the following figure:
   
   <<=== NOTE: Modify this key.
   
6. In the right pane, double-click the (Default) value.
7. 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 document and make sure that you completely remove the current value data.
     
8. Navigate to and delete the key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftActive SetupInstalled Components{44AF0969-CC51-11CF-AAFA-06AA00F6115C}
   
9. Exit the Registry Editor.
10. Restart the computer.

2. 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 the 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), in the "Protection" section, at the top of this writeup.
• 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), in the "Protection" section, at the top of this writeup.
  
  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.

3. 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.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan All Files."
2. Run a full system scan.
3. If any files are detected as infected with Backdoor.Beasty.B, click Delete.