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Published Nov 30, 2004 | Updated Sep 15, 2017

Worm:Win32/Gaobot.ZJ

Detected by Microsoft Defender Antivirus

Aliases: No associated aliases

Summary

Win32/Gaobot.ZJ.worm is a network worm that can spread across network connections by breaking weak passwords or by exploiting vulnerabilities described in several Microsoft Security Bulletins. The worm has backdoor capabilities that allow attackers to control the infected computer using IRC channels. The worm also acts as a bot on the IRC network, coordinated through the IRC command, to launch massive distributed denial of service (DDoS) attacks and retrieve personal and system information.
To manually recover from infection by Backdoor:Win32/Gaobot.ZJ.worm, 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 from your computer.
  5. Delete the worm registry entries.
  6. Scan with antivirus software.
  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.

End the worm process

Ending the worm process will help stop your computer from infecting other computers as well as 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 srss32.exe, and click End Process.

Delete the worm file from your computer

To delete the worm file from your computer
  1. Click Start, and click Run.
  2. In the Open field, type the <system folder>, for example, %windir%\system32
  3. Click OK.
  4. Click Name to sort files by name.
  5. If srss32.exe is in the list, delete it.
  1. On the Desktop, right-click the Recycle Bin and click Empty Recycle Bin.
  2. Click Yes.
If deleting any of these files fails, follow these steps to verify that the files are 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 files are not in the list.

Delete the worm registry entries

Backdoor:Win32/Gaobot.ZJ.worm creates entries in the Windows registry that attempt to run the worm every time your computer restarts. 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: ServRun
  5. Click Delete and click Yes to delete the value.
  6. Repeat steps 3 through 5 for registry key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
  7. Close the Registry Editor.

Scan with antivirus software

Run a full-system scan with an up-to-date antivirus product. If you do not have antivirus software installed, you can get it from several companies. For more information, see http://www.microsoft.com/athome/security/downloads/default.mspx

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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