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Published Jul 22, 2004 | Updated Sep 15, 2017

Worm:Win32/Mydoom.A2@mm

Detected by Microsoft Defender Antivirus

Aliases: W32/Mydoom@MM (McAfee) W32.Mydoom.A@mm (Symantec) WORM_MYDOOM.A (Trend Micro) Win32.Mydoom.A (CA)

Summary

Win32/Mydoom.A2@mm is a mass-mailing worm that sends itself to e-mail addresses it finds on the infected computer. The worm also installs a .dll that acts as a backdoor. After February 1, 2004, the worm attempts to perform a denial-of-service (DoS) attack against www.sco.com.
To manually recover from infection by Win32/Mydoom.A2@mm, perform the following steps:
  1. Disconnect from the Internet.
  2. End the worm process.
  3. Delete the worm files from your computer.
  4. Delete the worm registry entry.
  5. Take steps to prevent re-infection.

Disconnect from the Internet

To ensure that your computer is not actively infecting other computers, you should disconnect it from the Internet before proceeding.

End the worm process

Next you should end the worm process. This helps to stop your computer from infecting other computers. It also resolves the crashing, reboot, 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 the Processes tab.
  3. On the Processes tab, click Image Name to sort the running processes by name.
  4. Select the process taskmon.exe, and click End Process.
This ends the worm processes and stops the worm from running on your computer.

Delete the worm files from your 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 then click Run.
  2. In the Open field, type %System%
  3. Press Enter.
  4. Click the Name column to sort files by name.
  5. Find the file taskmon.exe and delete it.
This removes the worm code from your computer. If deleting taskmon.exe fails, use the following steps to verify that taskmon.exe is not running:
  1. Press CTRL+ALT+DEL once and click Task Manager.
  2. Click the Processes tab.
  3. Confirm that mschost.exe is not in the list.

Delete the worm registry entry

Win32/Mydoom.A2@mm creates an entry in the Windows registry that attempts to run the worm every time your computer restarts. This entry should be deleted.
To delete the worm registry entry
  1. Click Start, and then click Run.
  2. In the Open field, type regedit
  3. Press Enter.
  4. Navigate to the registry key: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  5. Right-click the value
    TaskMon %System%\taskmon.exe
    or
    TaskMon %Temp%\taskmon.exe
    and click Delete.
  6. Click Yes.
  7. Exit the registry.

Take steps to prevent re-infection

You should not reconnect your computer to the Internet until the computer is protected from re-infection.
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