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Discovered: August 14, 2003
Updated: February 13, 2007 12:15:53 PM
Also Known As: Backdor.IRCBot.gen [KAV], W32/Sluter.worm [McAfee]
Type: Worm
Systems Affected: Windows

W32.Randex.F is a network-aware worm that copies itself to the following locations:

  • \Admin$\system32
  • \c$\winnt\system32

using one of the following file names:

  • NETD32.EXE
  • ranger.exe

The worm will receive instructions from an IRC channel on a specific IRC server. One such command will trigger the worm to spread.

Antivirus Protection Dates

  • Initial Rapid Release version August 14, 2003
  • Latest Rapid Release version May 07, 2019 revision 006
  • Initial Daily Certified version August 14, 2003
  • Latest Daily Certified version May 07, 2019 revision 008
  • Initial Weekly Certified release date August 20, 2003

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

Technical Description

When W32.Randex.F is executed, it does the following:

  1. Copies itself as %System%\Winnt32.dat and one of the following:
    • %System%\NETFD32.EXE
    • %System%\NETD32.EXE
    • %System%\Msnv32.exe
    • %System%\bigbadvirus.exe

      Note: %System% is a variable. The worm 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. Calculates a random IP address for a computer to infect and tries to copy itself to the c$ or admin$ network share as one of the following:
    • Netfd32.exe
    • Netd32.exe
    • Msnv32.exe

  3. Attempts to authenticate itself to the randomly generated IP addresses using the passwords listed below. The worm attempts to use the NetUserEnum API to generate user names. If this fails, it will try to connect as Administrator. For each user name, the worm will try the following passwords:
    • 12345
    • password
    • computer

  4. Copies itself to computers that have weak administrator passwords, at the following locations:
    • \\<authenticated IP>\Admin$\system32
    • \\<authenticated IP>\c$\winnt\system32

      using one of the following file names:

    • NETFD32.EXE
    • Msnv32.exe
    • Netd32.exe

  5. Remotely schedules a task to run the worm on a newly infected computer.

  6. Adds one of the following values:
    • "MicrosoftNetwork Daemon for Win32" = "NETD32.EXE"
    • "MS_NETD_WIN32" = "netd32.EXE"
    • "Microsoft Netview Component v5.1"  = "msnv32.exe"
    • "This is a virus, please delete it" = "bigbadvirus.exe"
    • "metalrock has sex with camels" = "ranger.exe"

      to the registry keys:

    • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\

      so that the worm runs when you start Windows.

  7. Connects to a specific IRC channel on a specific IRC server to receive remote instructions, such as:
    • Ntscan: Performs the scan for the computers with weak administrator passwords and copies itself to these machines.
    • Syn: Performs a syn flood attack with a data size of 55808 bytes.
    • Sysinfo: Retrieves the infected machine's information, such as CPU speed, memory, and so on.

  8. Steals the CD key of the following games:
    • Command & Conquer Generals
    • Battlefield 1942 Road To Rome
    • Battlefield 1942
    • Unreal Tournament 2003
    • Half-Life


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.


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. Restart the computer in Safe mode or VGA mode.
  4. Run a full system scan and delete all the files detected as W32.Randex.F.
  5. Delete the values that were added to the registry.
For specific details on each of these steps, read the following instructions.

1. Disabling System Restore (Window XP)
If you are running 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 "How to turn off or turn on Windows XP System Restore ."

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. Restarting the computer in Safe mode or VGA mode
Shut down the computer and turn off the power. Wait for at least 30 seconds, then restart the computer in Safe mode or VGA mode.
  • For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, refer to the document, "How to start the computer in Safe Mode."
  • For Windows NT 4 users, restart the computer in VGA mode.

4. 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.Randex.F, click Delete.

5. Deleting the values from the registry

CAUTION : 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. 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

    Then click OK. (The Registry Editor opens.)

  3. Navigate to the key:


  4. In the right pane, delete any of the following values:
    • "MicrosoftNetwork Daemon for Win32" = "NETD32.EXE"
    • "MS_NETD_WIN32" = "netd32.EXE"
    • "Microsoft Netview Component v5.1"  = "msnv32.exe"
    • "This is a virus, please delete it" = "bigbadvirus.exe"
    • "metalrock has sex with camels" = "ranger.exe"

  5. Navigate to the key:


  6. In the right pane, delete any of the following values:

    "MicrosoftNetwork Daemon for Win32" = "NETD32.EXE"
    "Microsoft Netview Component v5.1"  = "msnv32.exe"
    "This is a virus, please delete it" = "bigbadvirus.exe"
    "MS_NETD_WIN32" = "netd32.EXE"
    "metalrock has sex with camels" = "ranger.exe"

  7. Exit the Registry Editor.

Writeup By: Scott Gettis