Technology See Inside Hacking the Lights Out: The Computer Virus Threat to the Electrical Grid Computer viruses have taken out hardened industrial control systems. The electrical power grid may be next By David M. Nicol Vincent LaForet Redux Pictures Last year word broke of a computer virus that had managed to slip into Iran’s highly secure nuclear enrichment facilities. Most viruses multiply without prejudice, but the Stuxnet virus had a specific target in its sights—one that is not connected to the Internet. Stuxnet was planted on a USB stick that was handed to an unsuspecting technician, who plugged it into a computer at a secure facility. Once inside, the virus spread silently for months, searching for a computer that was connected to a prosaic piece of machinery: a programmable logic controller, a special-purpose collection of microelectronics that commonly controls the cogs of industry—valves, gears, motors and switches. When Stuxnet identified its prey, it slipped in, unnoticed, and seized control. The targeted controllers were attached to the centrifuges at the heart of Iran’s nuclear ambitions. Thousands of these centrifuges are needed to process uranium ore into the highly enriched uranium needed to create a nuclear weapon. Under normal operating conditions, the centrifuges spin so fast that their outer edges travel just below the speed of sound. Stuxnet bumped this speed up to nearly 1,000 miles per hour, past the point where the rotor would likely fly apart, according to a December report by the Institute for Science and International Security. At the same time, Stuxnet sent false signals to control systems indicating that everything was normal. Although the total extent of the damage to Iran’s nuclear program remains unclear, the report notes that Iran had to replace about 1,000 centrifuges at its Natanz enrichment facility in late 2009 or early 2010. This is only a preview. Get the rest of this article now! Select an option below: Buy Digital Issue Customer Sign In *You must have purchased this issue or have a qualifying subscription to access this content It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com. Click here to access this article in its entirety through site license access. ADVERTISEMENT Scientific American is a trademark of Scientific American, Inc., used with permission © 2013 Scientific American, a Division of Nature America, Inc. All Rights Reserved.