Discovered: September 4, 2002
Updated: February 13, 2007 11:40:19 AM
Type: Trojan Horse
Systems Affected: Windows 2000, Windows 95, Windows 98, Windows NT, Windows XP
NOTE: These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
- Update the virus definitions.
- Do one of the following:
- Windows 95/98/Me: Restart the computer in Safe mode.
- Windows NT/2000/XP: Stop the Kernel32.exe Trojan process.
- Reverse the changes that the Trojan made to the registry.
- Run a full system scan, and delete all files that are detected as Backdoor.OptixPro.10.
For details on how to do this, read the following instructions.
To update the virus definitions:
There are two ways to do this:
- Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
- Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions have undergone full quality assurance testing by Symantec Security Response. They are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.
Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.
To restart in Safe mode or stop the process:
Windows 95/98/Me
Restart the computer in Safe mode. All Windows 32-bit operating systems, except for Windows NT, can be restarted in Safe mode. For instructions on how to do this, read the document
How to start the computer in Safe Mode.
Windows NT/2000/XP
To stop the Trojan process:
- Press Ctrl+Alt+Delete one time.
- Click Task Manager.
- Click the Processes tab.
- Double-click the Image Name column header to sort the processes alphabetically.
- Scroll through the list, and look for Kernel32.exe.
- If you find the file, click it, and then click End Process.
- Close the Task Manager.
To reverse the changes that the Trojan made to the registry:
Because the worm modified the registry so that you cannot run .exe files, you must first make a copy of the Registry Editor as a file with the .com extension, and then run that file.
To copy Regedit.exe to Regedit.com:
- Do one of the following, depending on which version of Windows you are running:
- Windows 95/98 users: Click Start, point to Programs, and click MS-DOS Prompt. A DOS window opens at the C:\Windows prompt. Go on to step 2 of this section.
- Windows Me users: Click Start, point to Programs, point to Accessories, and then click MS-DOS Prompt. A DOS window opens at the C:\Windows prompt. Go on to step 2 of this section.
- Windows NT/2000 users:
- Click Start, and click Run.
- Type the following, and then press Enter:
command
A DOS window opens.
- Type the following, and then press Enter:
cd \winnt
- Go on to step 2 of this section.
- Windows XP:
- Click Start, and click Run.
- Type the following, and then press Enter:
command
A DOS window opens.
- Type the following, and then press Enter after typing each one:
cd\
cd \windows
- Proceed to step 2 of this section.
- Type the following, and then press Enter:
copy regedit.exe regedit.com
- Type the following, and then press Enter:
start regedit.com
The Registry Editor will open in front of the DOS window. After you finish editing the registry, exit the Registry Editor, and then exit the DOS window, as well.
1. Proceed to the next section, "To edit the registry and remove keys and changes made by the Trojan," only after you have performed the previous steps.
NOTES:
- The Registry Editor will open in front of the DOS window. After you finish editing the registry and have closed the Registry Editor, then close the DOS window, as well.
- After you have removed the Trojan, then you may delete the Regedit.com file.
To edit the registry and remove keys and changes made by the Trojan:
The Registry
Editor should already be open.
CAUTION: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document
How to make a backup of the Windows registry for instructions.
- Navigate to and select the following key:
HKEY_LOCAL_MACHINE\Software\Classes\exefile\shell\open\command
CAUTION: The HKEY_LOCAL_MACHINE\Software\Classes key contains many subkey entries that refer to other file extensions. One of these file extensions is .exe. Changing this extension can prevent any files ending with an .exe extension from running. Make sure that you browse all the way along this path until you reach the \command subkey.
Modify the HKEY_LOCAL_MACHINE\Software\Classes\exefile\shell\open\command subkey that is shown in the following figure:
<<=== NOTE: Modify this key.
- In the right pane, double-click the (Default) value.
- Delete the current value data, and then type: "%1" %* (That is, type the following characters: quote-percent-one-quote-space-percent-asterisk.)
NOTES:
- Under Windows 95/98/Me/NT, the Registry Editor automatically encloses the value within quotation marks. When you click OK, the (Default) value should look exactly like this:
""%1" %*"
- Under Windows 2000/XP, the additional quotation marks will not appear. When you click OK, the (Default) value should look exactly like this:
"%1" %*
- Make sure that you completely delete all value data in the command key before you type the correct data. If you leave a space at the beginning of the entry, any attempt to run program files will result in the error message, "Windows cannot find .exe." If this happens to you, start over at the beginning of this document, and make sure that you completely remove the current value data.
- Exit the Registry Editor.
To scan for and delete the infected files:
- Start your Symantec antivirus program, and make sure that it is configured to scan all files.
- Run a full system scan.
- If any files are detected as infected with Backdoor.OptixPro.10, click Delete.
- Restart the computer.
NOTE: In some cases, you may have to reinstall your antivirus or firewall software.
Writeup By: Serghei Sevcenco