W32.HLLW.GOP.G@mm

Printer Friendly Page

Discovered: January 17, 2003
Updated: February 13, 2007 11:48:35 AM
Type: Worm
Systems Affected: Windows


W32.HLLW.GOP.G@mm is a mass-mailing worm that copies itself to the hard drive as %System%\WindowsAgent.exe. It also searches the network drives and copies itself to \Recycled\Notdelw.i.n.v.e.r.y.i.f.y.exe on any mapped drive on which it can find an operating system. Then, W32.HLLW.GOP.G@mm modifies the Win.ini file to run the worm at startup.

Antivirus Protection Dates

  • Initial Rapid Release version January 17, 2003
  • Latest Rapid Release version January 17, 2003
  • Initial Daily Certified version January 17, 2003
  • Latest Daily Certified version January 17, 2003
  • Initial Weekly Certified release date January 22, 2003

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

Writeup By: Douglas Knowles

Discovered: January 17, 2003
Updated: February 13, 2007 11:48:35 AM
Type: Worm
Systems Affected: Windows


When W32.HLLW.GOP.G@mm is executed, it does the following:

  1. Copies itself as %System%\WindowsAgent.exe.

    NOTE: %System% is a variable. The Trojan locates the System folder and copies itself 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. Creates the Drocerrbk.sys file, in which it stores stolen passwords.
  3. Adds the value:

    WindowsAgent   %System%\WindowsAgent.exe

    to the registry key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  4. Performs its mass-mailing routine. Mostly, the email message it sends will contain a subject and message in Chinese. The attachment will be a .bmp, .rtf, .doc, .txt, .gif, .jpeg, or .jpg file, which is taken from your computer.

    To the original file name, the worm adds a second file extension, either .exe or .lnk. For example, if the original file name is Birthday pic.bmp, the name of the attachment will be Birthday pic.bmp.exe or Birthday pic.bmp.lnk.

    The worm searches for email addresses in .htm and .html files, and in many different email mailbox files. After gathering all the email addresses the worm can find, it uses its own SMTP engine to send an email message that can be executed (on unpatched systems) when it is read by the recipient.

    NOTE: The worm takes advantage of the IFRAME vulnerability that allows Microsoft Outlook to automatically execute attachments. Information on this vulnerability can be found at: http://www.microsoft.com/windows/ie/downloads/critical/q290108/default.asp.
  5. Searches the network drives and copies itself to \Recycled\Notdelw.i.n.v.e.r.y.i.f.y.exe on any mapped drive on which it can find an operating system. Then, the worm sets that particular file to run at startup, by modifying the Win.ini file.


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: Douglas Knowles

Discovered: January 17, 2003
Updated: February 13, 2007 11:48:35 AM
Type: Worm
Systems Affected: Windows


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

  1. Update the virus definitions.
  2. Run a full system scan and delete all the files detected as W32.HLLW.GOP.G@mm.
    Delete the Drocerrbk.sys file.
  3. Delete the value:

    WindowsAgent   %System%\WindowsAgent.exe

    from the registry key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
For specific details on each of these procedures, 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 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.

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 W32.HLLW.GOP.G@mm, click Delete.
  4. Follow the instructions for your operating system:
    • Windows 95/98/Me/NT/2000
      • Click Start, point to Find or Search, and then click Files or Folders.
      • Make sure that "Look in" is set to (C:) and that "Include subfolders" is checked.
      • In the "Named" or "Search for..." box, type, or copy and paste, the file name: Drocerrbk.sys.
      • Click Find Now or Search Now.
      • Delete the displayed files.
    • Windows XP
      • Click Start, and then click Search.
      • Click All files and folders.
      • In the "All or part of the file name" box, type, or copy and paste, the file name: Drocerrbk.sys.
      • Verify that "Look in" is set to "Local Hard Drives" or to (C:).
      • Click "More advanced options."
      • Check "Search system folders."
      • Check "Search subfolders."
      • Click Search.
      • Delete the displayed files.
3. Deleting the value from the registry

CAUTION : 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. Read the document, "How to make a backup of the Windows registry ," for instructions.
  1. Click Start, and then click Run. (The Run dialog box appears.)
  2. Type regedit, and then click OK. (The Registry Editor opens.)
  3. Navigate to the key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  4. In the right pane, delete the value: WindowsAgent.
  5. Exit the Registry Editor.


Writeup By: Douglas Knowles