Welchia Worm Infects Automation Network
Although internet access is generally denied from the Automation Network, the firewall was opened up to an Automation engineer to get an application update. In addition to getting the update, he also brought in the Welchia worm.
The worm tried to automatically connect to the internet to download a fix for the MSBlaster worm. ALthough the traffic increased on the Automation network, there was no outage because access to the internet had been closed so the requested downloads did not take place.