We're gradually updating threat actor names in our reports to align with the new weather-themed taxonomy. Learn about Microsoft threat actor names
Worm:Win32/Mytob.CT@mm
Detected by Microsoft Defender Antivirus
Aliases: W32/Mytob.bp@MM (McAfee) Net-Worm.Win32.Mytob.bf (Kaspersky) W32.Mytob.CU@mm (Symantec)
Summary
Win32/Mytob.CT@mm is a mass-mailing worm that spreads by sending a copy of itself as an e-mail attachment to e-mail addresses that it finds on the infected 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.CT, follow these steps:
- Disconnect from the Internet.
- Restart your computer in safe mode.
- End the worm process.
- Delete the worm file.
- Delete the worm registry entries.
- Restart your computer.
- 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
- Remove all floppy disks and CDs from your computer, and then restart your computer.
- 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.
- From the Windows Advanced Options menu, select a safe mode option.
End the worm process
To end the worm process
- Press CTRL+ALT+DEL once and click Task Manager.
- Click Processes and click Image Name to sort the running processes by name.
- Select the process named "lien van de kelder.exe" and click End Process.
Delete the worm file
To delete the worm file
- Click Start, and click Run.
- In the Open field, type the name of the Windows system folder, for example, C:\Windows\System32
- Click OK.
- Click Name to sort files by name.
- Delete the file "lien van de kelder.exe" if it is in the list.
- On the Desktop, right-click the Recycle Bin and click Empty Recycle Bin.
- Click Yes to confirm.
If deleting the worm file fails, follow these steps to verify that the corresponding process is not running:
- Press CTRL+ALT+DEL once and click Task Manager.
- Click Processes and click Image Name to sort the running processes by name.
- Confirm that "lien van de kelder.exe" is not in the list.
Delete the worm registry entries
Win32/Mytob.CT@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
- On the Start menu, click Run.
- Type regedit and click OK.
- In the left pane, navigate to the key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run - In the right pane, right-click the following value, if it exists: http://www.lienvandekelder.be
- Click Delete and click Yes to delete the value.
- Repeat steps 3 through 5 for the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices - Close the Registry Editor.
Restart your computer
To restart your computer
- On the Start menu, click Shut Down.
- 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.