Detection:
Check for the existence of the registry key
"SOFTWARE\Microsoft\Windows\CurrentVersion\Run\windows auto update". Also check for the existence of the file "%systemroot%\system32\msblast.exe".
Retina Network Security Scanner has been updated to identify Blaster worm infections, as well as hosts vulnerable to the DCOM security hole that the Blaster uses to propagate.
http://www.eeye.com/html/Products/Retina/index.html
eEye has also released a free scanner to aid in the detection of vulnerable hosts:
http://www.eeye.com/html/Research/Tools/RPCDCOM.html
Removal:
Delete the following registry key:
"HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run"
Value: "windows auto update"
String: "msblast.exe"
Look for "msblast.exe" running in the task manager. If it is running, kill the process.
Delete the file "%systemroot%\system32\msblast.exe"
Prevention:
Install the Microsoft patch available from:
http://www.microsoft.com/technet/security/bulletin/MS03-026.asp
Where feasible, disable DCOM and filter the following ports:
TCP: 135, 139, 445, 593
UDP: 135, 445, 593, possible tftp (69)
To manually enable (or disable) DCOM for a computer:
Run dcomcnfg.exe. If you are running Windows XP or Windows Server 2003, perform these additional steps:
Click on the Component Services node under Console Root.
Open the Computers sub-folder.
For the local computer, right click on My Computer and choose Properties.
For a remote computer, right click on the Computers folder and choose New then Computer. Enter the computer name.
Right click on that computer name and choose Properties.
Choose the Default Properties tab.
Select (or clear) the Enable Distributed COM on this Computer check box.
If you will be setting more properties for the machine, click the Apply button to enable (or disable) DCOM. Otherwise, click OK to apply the changes and exit Dcomcnfg.exe.
Reboot.