Printer Friendly Page

Discovered: April 02, 2001
Updated: February 13, 2007 11:50:44 AM
Also Known As: W32/Scrambler.h@MM, Win32/Scrambler.F@mm
Type: Virus

W32.HLLP.Scrambler.F is a minor variant of the W32.HLLP.Scrambler virus. This Windows virus infects .exe files on local computers. It also exhibits worm-like behavior by sending itself through email using Microsoft Outlook and through Internet Relay Chat using mIRC. The Scrambler.vbs file is dropped by the virus, and if mIRC is installed, the Script.ini file is dropped in the mIRC program folder.

Antivirus Protection Dates

  • Initial Rapid Release version April 02, 2001
  • Latest Rapid Release version August 20, 2008 revision 017
  • Initial Daily Certified version April 02, 2001
  • Latest Daily Certified version August 20, 2008 revision 016

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

Writeup By: Cary Ng

Discovered: April 02, 2001
Updated: February 13, 2007 11:50:44 AM
Also Known As: W32/Scrambler.h@MM, Win32/Scrambler.F@mm
Type: Virus

W32.HLLP.Scrambler.F is a compressed version of W32.HLLP.Scrambler virus. The virus prepends itself to .exe files on local computers, and it drops two files: Scramble.vbs and Script.ini.

The virus also exhibits worm-like behaviors. The Scramble.vbs file uses MAPI calls to Microsoft Outlook, and it creates messages by iterating through all addresses in the Microsoft Outlook Address Book.

The subject of the email is:

Check this out, it's funny!

The attachment is the virus itself in the form of an executable file with a randomly-generated file name. The virus may also spread using mIRC by creating in the mIRC program folder the Script.ini file, which sends the polymorphic .exe file to other users.


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: Cary Ng

Discovered: April 02, 2001
Updated: February 13, 2007 11:50:44 AM
Also Known As: W32/Scrambler.h@MM, Win32/Scrambler.F@mm
Type: Virus

Norton AntiVirus detects the virus as W32.HLLP.Scrambler.F. The .vbs file is detected as VBS.Scrambler.

To remove this worm:

  1. Run LiveUpdate to make sure that you have the most recent virus definitions.
  2. Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
  3. Delete any files detected as W32.HLLP.Scrambler.F or VBS.Scrambler.
  4. If you use mIRC, delete the Script.ini file from the mIRC program folder.

Writeup By: Cary Ng