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Published Jul 12, 2004 | Updated Sep 15, 2017

Worm:Win32/Mydoom.A@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.A@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 file that acts as a backdoor. After February 1, 2004, the worm attempts a denial-of-service (DoS) attack against www.sco.com.
To manually recover from infection by Win32/Mydoom.A@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 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.

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 taskmon.exe, and click End Process.

Delete the worm files from your computer

After you end the worm process, delete the worm code from your computer.
To delete the worm files from your computer
  1. Click Start, and click Run.
  2. In the Open field, type %windir%
  3. Click OK.
  4. Click Name to sort files by name.
  5. If the file taskmon.exe is in the list, delete it.
  6. On the Desktop, right-click the Recycle Bin and click Empty Recycle Bin .
  7. Click Yes .
If deleting files fails, use the following steps to verify that taskmon.exe is not running:
  1. Press CTRL+ALTlt+DEL once and click Task Manager.
  2. Click Processes and click Image Name to sort the running processes by name.
  3. Confirm that taskmon.exe is not in the list.

Delete the worm registry entry

To delete the worm registry entry
  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
  4. In the right pane, right-click the value:
    TaskMon %System%\taskmon.exe
    or
    TaskMon %Temp%\taskmon.exe
  5. Select Delete.
  6. Click Yes to delete the value.
  7. Repeat steps 3 to step 6 for the following registry key: 
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  8. Close the Registry Editor.

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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