Severe threat Level,
High damage capabilities,
Dangers: Vulnerable Windows 2000 machines will experience system
instability due to the RPC service crash.

This worm come high on the heels of the Blaster virus and pretends to
fix it!

It attempts to download the DCOM RPC patch from Microsoft's Windows
Update Web site, install it, and then reboot the computer.
Checks for active machines to infect by sending an ICMP echo request,
or PING, which will result in increased ICMP traffic.
Attempts to remove W32.Blaster.Worm.

The resultant damage is that it causes system instability. Windows
2000 machines will experience system instability due to the RPC
service crash. and security setting are compromised since it installs
a TFTP server on all the infected machines.

For more information see
http://www.symantec.com/avcenter/venc/data/w32.welchia.worm.html

A virus removal tool have been created by Symantec