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Published Nov 13, 2005 | Updated Sep 15, 2017

Worm:Win32/Mytob.AJ@mm

Detected by Microsoft Defender Antivirus

Aliases: W32/Mytob.C.worm (Panda) Win32/MyDoom.BI!Worm (CA) Win32.Mytob.D (CA) Net-Worm.Win32.Mytob.c (F-secure) Net-Worm.Win32.Mytob.c (Kaspersky) W32/Mytob.gen@MM (McAfee) Mytob.D (Norman) W32/Mytob-C (Sophos) W32.Mytob.C@mm (Symantec) WORM_MYTOB.B (Trend Micro)

Summary

Win32/Mytob.AJ@mm is a mass-mailing network worm that targets computers running certain versions of Microsoft Windows. The worm spreads as an attachment through e-mail. It can also spread to computers that have not been patched for the Windows vulnerability described in Microsoft Security Bulletin MS04-011. Win32/Mytob.AJ@mm has a backdoor component that connects to an IRC server from the infected computer to receive commands from attackers.
To manually recover from infection by Win32/Mytob.AJ@mm, follow these steps:
  1. Disconnect from the Internet.
  2. Restart your computer in safe mode.
  3. End the worm process.
  4. Delete the worm file.
  5. Delete the worm registry entries.
  6. Restart your computer.
  7. 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 your computer in safe mode

To start your the 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

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 wfdmgr.exe if it exists, and click End Process.

Delete the worm file

To delete the worm file
  1. Click Start, and click Run.
  2. In the Open field, type the name of the Windows system folder, for example, C:\Windows\System32 
  3. Click OK.
  4. Click Name to sort files by name.
  5. Delete the file wfdmgr.exe if it is in the list.
  6. On the Desktop, right-click the Recycle Bin and click Empty Recycle Bin.
  7. Click Yes to confirm.
If deleting the file fails, follow these steps to verify that process wfdmgr.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 wfdmgr.exe is not in the list.

Delete the worm registry entries

Win32/Mytob.AJ@mm creates entries in the Windows registry that cause the worm to run automatically each time Windows starts. These entries should be deleted.
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
  4. In the right pane, right-click the following value, if it exists: LSA
  5. Click Delete and click Yes to delete the value.
  6. Repeat steps 3 through 5 for each of the following registry keys:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    HKEY_CURRENT_USER\SOFTWARE\Microsoft\OLE
    HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Control\Lsa
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\OLE
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
  7. Close the Registry Editor.

Restart your computer

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

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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