W32.Appix.Worm - Removal

NOTE: These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Do one of the following:
   • Windows 95/98/Me: Restart the computer in Safe mode.
   • Windows NT/2000/XP: Stop the worm process.
2. Reverse the changes that the worm made to the registry.
3. Do one of the following:
   • Windows 95/98/Me: Restart the computer in normal mode.
   • Windows NT/2000/XP: Restart your Symantec antivirus product.
4. Update the virus definitions.
5. Run a full system scan, and delete all files that are detected as W32.Appix.Worm or PHP.Appix.
   

For details on how to do this, read the following instructions.

To restart the computer in Safe mode or end the worm 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 worm process:

1. Press Ctrl+Alt+Delete one time.
2. Click Task Manager.
3. Click the Processes tab.
4. Double-click the Image Name column header to sort the processes alphabetically.
5. Scroll through the list, and look for the following names:
   • AppBoostTrojan (Please note that only 15 characters are displayed.)
   • Appboost.exe
6. For each of these processes that you find, click the name, and then click End Process.
7. Close the Task Manager.

To reverse the changes that the worm made to the registry:

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.

1. 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.
   
   Make sure that you modify the HKEY_LOCAL_MACHINE\Software\Classes\exefile\shell\open\command subkey that is shown in the following figure:
   
   <<=== NOTE: Modify this key.
   
2. In the right pane, double-click the (Default) value.
3. 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.
     
4. Navigate to the key
   
   HKEY_CURRENT_USER\Software\Microsoft\Mails
   
5. In the right pane, delete the value
   
   <random digit, e.g. 6>    <time when the worm was executed in an internal format>
   
6. Exit the Registry Editor.

To restart the computer or antivirus product:
Do one of the following:

• Windows 95/98/Me: Restart the computer as you normally would. Do not choose Safe mode this time, and allow the computer to start normally.
• Windows NT/2000/XP: Restart your Symantec antivirus product. The method for doing this depends on the product. Please see the product documentation for additional information.

To update the virus definitions:
All virus definitions receive full quality assurance testing by Symantec Security Response before being posted to our servers. There are two ways to obtain the most recent virus definitions:

• Run LiveUpdate, which is the easiest way to obtain virus definitions. These virus definitions 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 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 scan for and delete the infected files:

1. Start your Symantec antivirus program, and make sure that it is configured to scan all files.
   • Norton AntiVirus consumer products: Read the document How to configure Norton AntiVirus to scan all files.
   • Symantec enterprise antivirus products: Read the document How to verify a Symantec Corporate antivirus product is set to scan All Files.
2. Run a full system scan.
3. If any files are detected as infected with W32.Appix.Worm or PHP.Appix, click Delete.

Technical Details