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Published Oct 17, 2005 | Updated Sep 15, 2017

Worm:Win32/Mytob.DR@mm

Detected by Microsoft Defender Antivirus

Aliases: W32/Mytob.gen@MM (McAfee) W32/Mytob.HC (Norman) W32/Mytob.FD.worm (Panda) Net-Worm.Win32.Mytob.bi (Kaspersky) W32/Mytob-EP (Sophos) W32.Mytob.EE@mm (Symantec) WORM_MYTOB.EP (Trend Micro) Win32/Mytob.40448!Worm (CA) Win32.Mytob.EQ (CA) Net-Worm.Win32.Mytob.bi (F-secure)

Summary

Win32/Mytob.DR@mm is a mass-mailing worm that targets computers running certain versions of Windows. The worm spreads by sending a copy of itself as an attachment to e-mail addresses found on the computer.  The worm has a backdoor component that connects to an IRC server from an infected computer to receive commands from attackers.
To manually recover from infection by Win32/Mytob.DR, follow these steps:
  1. Disconnect from the Internet.
  2. Restart your computer in safe mode.
  3. Find the name of the worm copy on your computer.
  4. End the worm process.
  5. Delete the worm file.
  6. Delete the worm registry entries.
  7. Restart your computer.
  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 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.

Find the name of the worm copy on your computer

To find the name of the worm copy
  1. On the Start menu, click Run.
  2. Type regedit,and click OK.
  3. In the left pane of the Registry Editor, navigate to the key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  4. In the Name column in the right pane, locate the following value, if it exists: WINDOWS SYSTEM
  5. In the Data column in the right pane, the string across from the value "WINDOWS SYSTEM" is the <worm copy file name>. This is the file name of the worm copy that Win32/Mytob.DR placed on your computer.

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 named <worm copy file name>.
  4. Click End Process.

Delete the worm file

To delete the worm file
  1. Find and delete all files on your computer named <worm copy file name>. 
  2. On the Desktop, right-click the Recycle Bin and click Empty Recycle Bin.
  3. Click Yes to confirm.
If deleting the worm file fails, follow these steps to verify that the file 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 <worm copy file name> is not in the list.

Delete the worm registry entries

Win32/Mytob.DR 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. In the left pane of the Registry Editor, again navigate to the key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  2. In the right pane, right-click the following value, if it exists: WINDOWS SYSTEM
  3. Click Delete and click Yes to delete the value.
  4. Repeat steps 1 through 3 for the following registry key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\RunServices
  5. 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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