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Published Jul 23, 2004 | Updated Sep 15, 2017

Worm:Win32/Randex.AK

Detected by Microsoft Defender Antivirus

Aliases: W32.Randex.gen (Symantec) WORM_SDBOT.EU (Trend Micro) W32/Sdbot.worm.gen.r (McAfee) W32/SdBot-Fam (Sophos)

Summary

Win32/Randex.AK is a network worm that targets computers running certain versions of Microsoft Windows. The worm scans IP addresses randomly to spread to writeable network shares that have weak passwords. The worm also has backdoor capabilities that allow attackers to control an infected computer through an IRC channel.
To manually recover from infection by Win32/HLLW.Randex.AK, 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 files from the hard disk.
  5. Delete the worm registry entry.
  6. Scan network shares with an antivirus program. 
  7. Take steps to prevent re-infection.

Disconnect from the Internet

To help ensure that your computer is not actively infecting other computers, you should 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 the process spool.exe and click End Process. 
On Windows 9x, this worm registers itself as a service so that the process is hidden from Task Manager. You may need to use a third-party process viewer to terminate the worm process.

Delete the worm files from the computer

Once you have stopped the worm from running, you should delete the worm code from your computer.
To delete the worm files from the hard disk
  1. Click Start, and click Run.
  2. In the Open field, type %windir%\system32
  3. Click OK.
  4. Click Name to sort files by name.
  5. If any of the following files are in the list, delete them:
    spool.exe
    GT.exe
    moo.dat
If deleting files fails, use the following steps to verify that spool.exe is not running:
  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. Confirm that none of the following files is in the list:
    spool.exe
    GT.exe
    moo.dat

Delete the worm registry entry

Win32/HLLW.Randex.AK creates several entries in the Windows registry that attempt to run the worm every time your computer restarts.
To delete the worm registry entries
  1. On the Start menu, click Run.
  2. Type regedit and click OK.
  3. In the left pane, navigate to the key:
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    In the right pane, right-click the value: Spooler Subsystem = spool.exe
  4. Select Delete and click Yes to delete the value.
  5. Repeat steps 3 and 4 for the following registry key:           
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices        
  6. Close the Registry Editor.

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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