The Blaster worm has been detected on campus. This worm attacks un-patched operating systems that are open to the RPC vulnerability.

Manual Removal

Important Notes:

W32.Blaster.Worm also known as W32/Lovsan.worm [McAfee], Win32.Poza [CA], Lovsan [F-Secure], WORM_MSBLAST.A [Trend], W32/Blaster-A [Sophos], W32/Blaster [Panda]

W32.Blaster.Worm (msblast.exe), and the W32.Blaster.B.Worm Penis32.exe) a variant of W32.Blaster.Worm, and the W32/Nicha.Worm exploits the DCOM RPC vulnerability (described in Microsoft Security Bulletin MS03-039) using TCP port 135.

To resolve this error, you first need to use the command:

shutdown -a

to stop the system from shutting down so that you can patch the computer and remove the virus. You must download and install the patch. In many cases, you will need to do this before you can continue with the removal instructions. If you cannot apply the patch you can also temporarily disable DCOM which will protect you from the exploit. If you are not able to remove the infection or prevent re-infection using the following instructions, first download and install the patch.

Because of the way the worm works, it may be difficult to connect to the Internet to obtain the patch, definitions, or removal tool before the worm shuts down the computer. It has been reported that, for users of Windows XP, activating the Windows XP firewall may allow you to download and install the patch, obtain virus definitions, and run the removal tool. This may also work with other firewalls, although this has not been confirmed. Disable System Restore (Windows XP).

Two of the new vulnerabilities might allow arbitrary code to be run; one of the new vulnerabilities might result in a denial of service without patch KB824146 these vulnerabilities were found after the Blaster Worm.

The update files are also available from the Topaz server at:

1. Disconnect your computer from the internet!
2. Disable System Restore for Windows XP.
3. End the Trojan process.
4. Run a full system scan and delete all the files detected as W32.Blaster.Worm.
5. Reverse the changes that the Trojan made to the registry.

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

1. Disconnect the Cat5 or Thin wire connection from the back of your computer.

2. Disabling System Restore (Windows XP) (Only needed if you use an automatic removal tool.)

If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.

2. Ending the Worm process

To end the Trojan process:

Press Ctrl+Alt+Delete once.
Click Task Manager.
Click the Processes tab.
Double-click the Image Name column header to alphabetically sort the processes.
Scroll through the list and look for any of the following files:

• MSBLAST.EXE
• PENIS32.EXE
• TEEKIDS.EXE
• MSPATCH.EXE
• MSLAUGH.EXE
• ENBIEI.EXE

If you find the file, click it, and then click End Process.
Exit the Task Manager.

3. Scan for and delete infected files. You should find two files in \windows\system32\msblast.exe and \windows\prefetch\msblast.pf, delete these files or any of the files listed above.

4. Reversing the changes made to the registry

Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read the document, "How to make a backup of the Windows registry," for instructions on backing up the registry first if you choose to.
 

Click Start, and then click Run. (The Run dialog box appears.)

Type regedit
Then click OK. (The Registry Editor opens.)

Navigate to the key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

In the right pane, delete the value:

"windows auto update"="msblast.exe" or any of the other files listed above

Disable DCOM so you can get out on the internet to patch your operating system.

Navigate to the key:

HKEY_LOCAL_MACHINE\Software\Microsoft\OLE\

In the right pane, change the value to:

"EnableDCOM"="N"

Exit the Registry Editor.

Re-boot your computer and re-connect to the internet.

End of manual instructions.

Automatic Removal

Symantec has a clean tool to fix the Blaster worm available at:
http://securityresponse.symantec.com/avcenter/venc/data/w32.blaster.worm.removal.tool.html

A copy of the tool is also available at fixblast.exe.

McAfee has a cleaner tool to remove the Blaster Worm along with many other recent Worms and Trojans at:
http://download.nai.com/products/mcafee-avert/stinger.exe

A copy of the Stinger tool is also available on Topaz at stinger.exe

The instructions from the Symantec site are as follows:

Symantec Security Response

W32.Blaster.Worm Removal Tool

Discovered on: August 11, 2003

Last Updated on: August 11, 2003 08:01:58 PM PDT

Symantec Security Response has developed a removal tool to clean the W32.Blaster.Worm infections.

The W32.Blaster.Worm Removal Tool does the following: Terminates the W32.Blaster.Worm viral processes. Deletes the W32.Blaster.Worm files. Deletes the dropped files. Deletes the registry values that the worm added. Command-line switches available with this tool     Switch   Description /HELP, /H, /? Displays the help message. /NOFIXREG Disables registry repair (the use of this switch is not recommended). /SILENT, /S Enables silent mode. /LOG=<path name> Creates a log file where <path name> is the location in which to store the tool's output. By default, this switch creates the log file Fxbgbear.log in the same folder from which the removal tool was executed. /MAPPED Scans mapped network drives (the use of this switch is not recommended--see notes). /START Forces the tool to start scanning immediately. /EXCLUDE=<path> Excludes the specified <path> from scanning (the use of this switch is not recommended). NOTE: Using the /MAPPED switch does not ensure the complete removal of the virus on the remote computer, because: Scanning the mapped drives scans the mapped folders only. This action may not include all the folders on the remote computer, leading to missed detections. If a viral file is detected on the mapped drive, the removal will fail if a program on the remote computer uses this file. For these reasons, run the tool on every computer.

Obtaining and running the tool

NOTE: You need administrative rights to run this tool on Windows 2000, or Windows XP.

Download the FixBlast.exe file from:

If you are running Windows XP, then disable System Restore. Refer to the section, "System Restore option in Windows Me/XP," for additional details.

CAUTION: If you are running Windows XP, we strongly recommend that you do not skip this step. The removal procedure may be unsuccessful if Windows XP System Restore is not disabled, because Windows prevents outside programs from modifying System Restore.

Double-click the FixBlast.exe file to start the removal tool.

Click Start to begin the process, and then allow the tool to run.

NOTE: If, when running the tool, you see a message that the tool was not able to remove one or more files, run the tool in Safe mode. Shut down the computer, turn off the power, and wait 30 seconds. Restart the computer in Safe mode and run the tool again. All the Windows 32-bit operating systems, except Windows NT, can be restarted in Safe mode. For instructions, read the document "How to start the computer in Safe Mode."

Restart the computer.

Run the removal tool again to ensure that the system is clean.
If you are running Windows XP, then re-enable System Restore.
When the tool has finished running, you will see a message indicating whether W32.Blaster.Worm infected the computer. In the case of a worm removal, the program displays the following results:

Total number of the scanned files
Number of deleted files
Number of terminated viral processes
Number of fixed registry entries

System Restore option in Windows Me/XP

Users of Windows Me and Windows XP should temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, in some cases, online scanners may detect a threat in the System Restore folder even though you scanned your computer with an antivirus program and did not find any infected files.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• How to disable or enable Windows Me System Restore.
• How to turn off or turn on Windows XP System Restore.

For additional information and an alternative to disabling Windows Me System Restore, read the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Q263455)."

How to run the tool from a floppy disk

Insert the floppy disk, which contains the FixBlast.exe file, in the floppy disk drive.

Click Start, and then click Run.

Type the following:

a:\FixBlast.exe

and then click OK:

NOTES:

There are no spaces in the command, a:\FixBlast.exe.

If you are using Windows Me and System Restore remains enabled, you will see a warning message. You can choose to run the removal tool with the System Restore option enabled or exit the removal tool.

Click Start to begin the process, and then allow the tool to run.

If you are using Windows Me, then re-enable System Restore.

After you remove the worm you should disable DCOM by:

(Note: Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only.)

Click Start, and then click Run. (The Run dialog box appears.)

Type regedit

Then click OK. (The Registry Editor opens.)

Navigate to the key:

HKEY_LOCAL_MACHINE\Software\Microsoft\OLE\

In the right pane, change the value to:

"EnableDCOM"="N"

Exit the Registry Editor.

Re-boot your computer and re-connect to the internet.