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Published Feb 13, 2005 | Updated Sep 15, 2017

Backdoor:Win32/Gaobot.DC

Detected by Microsoft Defender Antivirus

Aliases: Gaobot.CYH (Panda) W32/Gaobot.worm.gen.j (McAfee) W32.HLLW.Gaobot (Symantec)

Summary

Backdoor:Win32/Gaobot.DC is a backdoor Trojan that targets certain versions of Microsoft Windows. The Trojan allows remote attackers to infect and control a computer through an IRC channel. When the Trojan receives certain commands, it may spread to other computers or target certain Web sites for denial of service (DoS) attacks.
To manually recover from infection by Backdoor:Win32/Gaobot.DC, perform the following steps:
  1. Disconnect from the Internet.
  2. End the Trojan process.
  3. Delete the Trojan file from your computer.
  4. Delete the Trojan registry entries.
  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 Trojan process

Ending the Trojan process will help stop your computer from infecting other computers as well as resolve the crashing, rebooting, and performance degradation issues caused by the Trojan.
To end the Trojan 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 process Mnksvc32.exe 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 %windir%\system32.
  3. Click OK.
  4. Click Name to sort files by name.
  5. If Mnksvc32.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 the file fails, follow these steps to verify that Mnksvc32.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 Mnksvc32.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:
    Mekio Startups = Mnksvc32.exe
  5. Click Delete and click Yes to delete the value.
  6. In the left pane, navigate to the key: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
  7. In the right pane, right-click the following value, if it exists:
    Mekio Startups = Mnksvc32.exe
  8. Click Delete and click Yes to delete the value.
  9. 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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