How vulnerable are facilities to Internet worms or viruses and what can be done to prevent it?
On multiple occasions control systems have been invaded by Internet worms and viruses. These occurrences are well documented and verified by NERC and, over the past few years, a significant number of electric utility real-time networks have been compromised. In two well-known electric utility cases, the SQL Slammer worm penetrated real-time networks and was able to block SCADA traffic. In another instance, a virus disabled two monitoring systems at a U.S. nuclear power plant.
