The W32.Blaster worm may have contributed to the cascading effect of the US blackout on 14 August, government and industry experts have revealed.
On the day of the blackout, Blaster degraded the performance of several communications lines linking key data centres used by utility companies to manage the power grid.
"It didn't affect the systems internally, but it most certainly affected the timeliness of the data they were receiving from other networks," said Gary Seifert, a researcher at the US Department of Energy, referring to flow-control and load-balancing data that's transmitted over public telecommunications networks.
He added that "it certainly compounded the problems" relating to the congestion of key communications links used by utilities to co-ordinate contingency efforts.
The inability of critical control data to be exchanged quickly across the grid could have hampered the operators' ability to prevent the cascading effect of the blackout. Seifert stressed, however, that no one is certain at this point what caused the blackout.
A former Bush administration adviser who has consulted with the US Department of Homeland Security on the power grid issue said the Blaster worm also hampered the ability of utilities in the New York region to restore power in good time because some of those companies were running Windows-based control systems with Port 135 open - the port through which the worm attacked systems.
Carol Murphy, vice president of government affairs at the New York Independent System Operator, acknowledged that Blaster affected the utility but said the problem was handled quickly, with no impact on power restoration operations.
Joe Petta, a spokesman for Consolidated Edison Company of New York, said there were "absolutely no computer-related problems of any sort that delayed our restoration effort".
The control systems referred to by Seifert, also known as supervisory control and data acquisition (Scada) systems, are used to manage large industrial operations. They are often based on Windows 2000 or XP operating systems and rely on commercial data links, including the internet and wireless systems, for exchanging information.
Scott Charney, chief security strategist at Microsoft, said Blaster raised a security and network performance issue for all Microsoft customers and that there was nothing unique about the electricity industry.
Joe Weiss, a control system expert and executive consultant at Kema Consulting, said that the power grid fell victim to a worm that attacked the communications infrastructure.
However, a number of energy industry experts, who wished to remain anonymous, said the control systems themselves are also at risk, admitting that the January outbreak of the Slammer worm affected the real-time control environment of "several" utility companies around the country.
Dan Verton writes for Computerworld