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Published Jul 14, 2004 | Updated Sep 15, 2017

Worm:Win32/Randex.FI

Detected by Microsoft Defender Antivirus

Aliases: W32.Randex.gen (Symantec) W32/Sdbot-MD (Sophos) WORM_RANDEX.AK (Trend Micro)

Summary

Win32/Randex.FI.worm is a network worm that targets computers running certain versions of Microsoft Windows. The worm attempts to spread by randomly scanning IP addresses for writeable network shares with weak passwords. The worm has backdoor capabilities that allow attackers to control the infected computer through an IRC channel. The worm also restricts some security applications from running on infected computers.
To manually recover from infection by Win32/Randex.FI.worm, perform the following steps:
  1. Disconnect from the Internet.
  2. Restart the computer in safe mode.
  3. End the worm process.
  4. Delete the worm file from the computer.
  5. Delete the worm registry entries.
  6. Restart the computer. 
  7. Scan network shares with an antivirus program. 
  8. Take steps to prevent re-infection.

Disconnect from the Internet

To help ensure that your computer is not actively infecting other computers, disconnect it from the Internet before proceeding. Print this Web page or save a copy on your computer; then unplug your network cable and disable your wireless connection. You can reconnect to the Internet after completing these steps.

Restart the computer in safe mode

To start your computer in safe mode
  1. Remove all floppy disks and CDs from your computer, and then restart your computer.
  2. When prompted, press F8. If Windows starts without displaying the Please select the operating system to start menu, restart your computer. Press F8 after the firmware POST process completes, but before Windows displays graphical output.
  3. From the Windows Advanced Options menu, select a safe mode option.

End the worm process

Ending the worm process will help stop your computer from infecting other computers as well as resolve the crashing, rebooting, and performance degradation issues caused by the worm.
To end the worm process
  1. Press CTRL+ALT+DEL once and click Task Manager.
  2. Click Processes and click Image Name to sort the running processes by name.
  3. Select process msngmsg.exe, and then click End Process.

Delete the worm file from the computer

To delete the worm file from the hard disk
  1. Click Start, and then click Run.
  2. In the Open field, type %Windir%\system32
  3. Click OK.
  4. Click Name to sort files by name.
  5. If the file msngmsg.exe is in the list, delete it.

Delete the worm registry entry

Win32/Randex.FI.worm creates several entries in the Windows registry that attempts to run the worm every time your computer restarts. Also, it adds some security applications to the DisallowRun or RestrictRun entries. These entries should be deleted.
To delete the worm registry entries
  1. On the Start menu, click Run.
  2. For Windows 9x and Windows ME, type command and click OK.
    For Windows 2000, Windows NT, or Windows XP, type cmd and click OK. 
  3. At the command prompt, type copy %windir%\regedit.exe regedit.com|regedit.com.
  4. In the left pane of Registry Editor, navigate to the key:
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    In the right pane, right-click the value:
    System-Config = msngmsg.exe
  5. Select Delete and click Yes to delete the value.
  6. Repeat step 4 to step 6 for the following two registry keys:
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  7. In the left pane of Registry Editor, navigate to the key:
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
    In the right pane, right-click the value:
    COM Service = gayZZ.exe
  8. Select Delete and click Yes to delete the value.
  9. Repeat steps 7 and 8 for the following registry key:
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
  10. In the left pane of Registry Editor, navigate to registry key:
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\DisallowRun
    In the right pane, delete any entry that contains any of the following strings: 
    11. avpcc.exe
    cfgwiz.exe
    navapw32.exe
    netstat.exe
    ogrc.exe
    pccclient.exe
    pccguide.exe
    regedit.exe
    tds-3.exe
    thguard.exe 
  11. Repeat step 10 for the following registry key:
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\RestrictRun
  12. Close the Registry Editor.

Restart the computer

To restart the computer
  1. On the Start menu, click Shut Down.
  2. Select Restart from the drop-down list and click OK.

Scan network shares with an antivirus program

  1. On the Start menu, click Run.
  2. Type cmd and click OK.
  3. Type net share
  4. Run an antivirus program to scan the resource locations of listed shares.

Take steps to prevent re-infection

Do not reconnect your computer to the Internet until the computer is protected from re-infection. See the "Preventing Infection" section for more information. 
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