W32.HLLW.BenfGame.B

Printer Friendly Page

Discovered: June 02, 2003
Updated: February 13, 2007 12:01:54 PM
Also Known As: Worm.Win32.Fasong.a [KAV]
Type: Worm
Systems Affected: Windows


W32.HLLW.BenfGame.B is written in the Delphi programming language. It has a password-stealing component and a worm component. W32.HLLW.BenfGame.B spreads to all the mapped and network-shared drives under an assortment of randomly generated filenames.

Antivirus Protection Dates

  • Initial Rapid Release version June 03, 2003
  • Latest Rapid Release version August 20, 2008 revision 017
  • Initial Daily Certified version June 03, 2003
  • Latest Daily Certified version August 20, 2008 revision 016
  • Initial Weekly Certified release date June 03, 2003

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

Writeup By: Maryl Magee

Discovered: June 02, 2003
Updated: February 13, 2007 12:01:54 PM
Also Known As: Worm.Win32.Fasong.a [KAV]
Type: Worm
Systems Affected: Windows


The password-stealing component of W32.HLLW.BenfGame.B only applies when Chinese ICQ (OICQ) is installed. The Trojan sends the passwords to its creator via OICQ. The sent information for the password stealer is stored in the file, Msread.dt.

The worm component is independent of the Trojan component. When the worm is run, it does the following:

  1. Creates shares for the local and network drives.

  2. Copies itself to randomly selected folders on all the mapped and shared drives.

  3. Copies itself with filenames, composed of random letters, such as Xwsqz.exe.

  4. Creates the file, C:\Filedebug, with a list of the filenames that the worm created.

  5. Randomly registers some of the dropped files as processes.

  6. Makes the following modifications to these registry keys:

    HKEY_CLASSES_ROOT\txtfile\shell\open\command
    Replaces the reference to notepad.exe with one of the random filenames that the worm created.

    HKEY_CLASSES_ROOT\chm.file\shell\open\command
    Replaces the references to hh.exe with one of the random filenames that the worm created.

    HKEY_CLASSES_ROOT\scrfile\shell\open\command
    Changes the key to include one of the random filenames that the worm created, so that the key is <garbage file name> %1".

    HKEY_CLASSES_ROOT\regfile\shell\open\command
    Replaces the reference to regedit.exe with one of the random filenames that the worm created.

    HKEY_CLASSES_ROOT\inifile\shell\open\command
    Replaces the reference to any application with one of the random filenames that the worm created.

    HKEY_CLASSES_ROOT\exefile\shell\open\command
    Changes the key to include one of the random filenames that the worm created, so that the key is <garbage file name> "%1" %*".

  7. Adds a value, which refers to the worm, to the registry key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    The value has a randomly chosen name, and the Value data is not always the same. For example, the file Qwoes.exe might have a Value data of "C:\program files\Apflsw.exe."

  8. Adds the registry key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\win70\workfile

    with a random Value.

  9. Tries to disable the following NT processes:
    • kav9x.exe
    • kavsvc9x.exe
    • kavsvcui.exe
    • kav32.exe
    • smenu.exe
    • ravmon.exe
    • passwordguard.exe
    • vpc32.exe
    • watcher.exe

  10. Creates the file, called Autorun.inf, in the root of all the drives, except the C: drive.

    This file contains the text:

    [autorun]
    OPEN= <random file name generated by the worm>


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: Maryl Magee

Discovered: June 02, 2003
Updated: February 13, 2007 12:01:54 PM
Also Known As: Worm.Win32.Fasong.a [KAV]
Type: Worm
Systems Affected: Windows



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

  1. Disable System Restore (Windows Me/XP).
  2. Update the virus definitions.
  3. Run a full system scan and delete all the files detected as W32.HLLW.BenfGame.B. Delete the Autorun.inf file from the root of all the drives, except drive C, if it exists.
  4. Reverse the changes that were made to the registry.

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

1. Disabling System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder ," Article ID: Q263455.

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 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: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

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.
  2. Run a full system scan.
  3. If any files are detected as infected with W32.HLLW.BenfGame.B, click Delete.
  4. Delete the Autorun.inf file from the root of all the drives, except drive C, if it exists.

4. Reversing the changes made to the registry

Copying Regedit.exe to Regedit.com and editing the registry
Because the worm modified the registry, first make a copy of the Registry Editor as a file with the .com extension, and then run the file.
  1. Do one of the following, depending on the version of Windows you are running:
    • 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 b 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 b 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 b 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 b 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 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.

  4. 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."

  5. Next you must restore to their original values all of the keys that the worm modified. Navigate to and select in turn each of the following keys, and restore them to the values that are shown for each one:

    Key:
    HKEY_CLASSES_ROOT\txtfile\shell\open\command
    Restore value to: notepad.exe %1

    Key: HKEY_CLASSES_ROOT\chm.file\shell\open\command
    Restore value to: hh.exe %1

    Key: HKEY_CLASSES_ROOT\scrfile\shell\open\command
    Restore value to: %1/S

    Key: HKEY_CLASSES_ROOT\regfile\shell\open\command
    Restore value to:  regedit.exe %1

    Key: HKEY_CLASSES_ROOT\inifile\shell\open\command
    Restore value to: notepad.exe %1

    Key: HKEY_CLASSES_ROOT\exefile\shell\open\command
    Restore value to: %1 % *

  6. Delete the registry key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\win70\workfile

  7. Navigate to the key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

  8. In the right pane, delete the value that refers to the worm.

  9. Exit the Registry Editor.


Writeup By: Maryl Magee