W32.Tkbot.Worm - Removal

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Update the virus definitions.
2. Restart the computer in Safe mode, or stop the Firedaemon MSTask and Firedaemon Rundll services.
3. In a command window, change to the C:\Program Files\Microsoft\Update folder, and then run the command:
   
   cacls DLL /T /G Administrator:F
   
4. Run a full system scan and delete all the files detected as W32.Tkbot.Worm.
5. Drag the C:\Program Files\Microsoft folder to the Recycle bin, and then empty the Recycle bin.

For specific details on each of these procedures, read the following instructions.

1. Updating the virus definitions

Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
• Running LiveUpdate, which is the easiest way to obtain the virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate), in the "Protection" section, at the top of this writeup.
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater), in the "Protection" section, at the top of this writeup.
  
  The 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.

2. Restarting the computer in Safe mode or stopping the services

Windows 2000
Restart the computer in Safe mode. All the 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 4.0
1. Click Start, and then click Run.
2. Type cmd
   
   Then click OK. (A command window opens.)
   
3. Type net start
   
   Then press Enter.
   
4. In the list that appears, look for these two services:
   • FireDaemon Services: MsTaskMgr
   • FireDaemon Services: Rundll
     
For each one you find, type the command:

net stop "<name of service>"

For example, if you see Firedaemon MSTask in the list, type the following line at the command prompt:

net stop "Firedaemon Services: MSTaskMgr"

3. Running the cacls DLL /T /G Administrator:F command

1. If the command window is not already open, type command
   
   Then click OK.
   
2. Type the following lines (pressing Enter after typing each one):
   
   cd C:\Program Files\Microsoft\Update
   cacls DLL /T /G Administrator:F
   
   Click Yes if you see a confirmation message.
   
   NOTES:
   • If the Program Files folder is in a different location, make the appropriate substitution.
   • Use the root Admin name in place of Administrator, if appropriate.
     

4. Scanning for and deleting the infected files

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that 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.Tkbot.Worm, click Delete. (You should find at least 13 files in addition to Tk1.exe.)

5. Dragging the C:\Program Files\Microsoft folder to the Recycle bin

1. Start Windows Explorer.
2. Locate the C:\Program Files\Microsoft folder and drag and drop it into the Recycle bin. A warning from the OS will state that the Update folder is a "system" folder. Click Yes to continue with the operation.
3. Empty the Recycle bin.
4. If you are running Windows 2000, restart the computer in Normal mode.

Technical Details