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Published Jun 06, 2005 | Updated Sep 15, 2017

Backdoor:Win32/Rbot.LK

Detected by Microsoft Defender Antivirus

Aliases: W32/Sdbot.worm.gen.y (McAfee) W32.Spybot.PKC (Symantec) Win32/RBot.121504!Worm (CA)

Summary

Backdoor:Win32/Rbot.LK is a backdoor Trojan that targets computers running certain versions of Microsoft Windows. This Trojan can spread to a computer by trying weak passwords. The Trojan can also connect to a computer through an open port, and then connect to an IRC server and join a channel to receive commands.
To manually recover from infection by Backdoor:Win32/Rbot.LK, perform the following steps:
  • Disconnect from the Internet.
  • Restart the computer in safe mode.
  • End the Trojan process.
  • Delete the Trojan file from your computer.
  • Delete the Trojan registry entries.
  • Restart the 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 the computer in safe mode

To start your 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 Trojan process

Ending the Trojan process will help stop your computer from infecting other computers and 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 msupdtm.exe if it exists, and click End Process.

Delete the Trojan file from your computer

To delete the Trojan file from your computer
  1. Click Start, and click Run.
  2. In the Open field, type the name of the system folder, for example, C:\windows\system32.
  3. Click OK.
  4. Click Name to sort files by name.
  5. Delete the file <system folder>\msupdtm.exe, if it is present.
  6. On the Desktop, right-click the Recycle Bin and click Empty Recycle Bin.
  7. Click Yes to confirm. 
If deleting the files fails, use the following 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 the file <system folder>\msupdtm.exe is not in the list.

Delete the Trojan registry entries

To delete the Trojan 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:
    Microsoft System  msupdtm.exe
  5. Click Delete and click Yes to delete the value.
  6. Repeat steps 3 to 5 for the following registry keys:
    HKEY_CURRENT_USER\SOFTWARE\Microsoft\OLE
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
  7. Close the Registry Editor.

Restart the 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

You should 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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