But in recent years, terrorists have expressed interest in a range of computer targets. Al Qaeda documents from 2002 suggest cyber-attacks on various targets, including the electrical grid and financial institutions, according to a translation by the IntelCenter, an Alexandria firm that studies terrorist groups.
A government advisory panel has concluded that a foreign intelligence service or a well-supported terrorist group "could conduct a structured attack on the electric power grid electronically, with a high degree of anonymity, and without having to set foot in the target nation," according to a report last year by the Government Accountability Office, the investigative arm of Congress.
California, even without the work of terrorists or hackers, can teeter near blackouts on its aging grid.
(Mike Blake -- Reuters)
Cyber-security specialists and government officials said that cyber-attacks are a concern across many industries but that the threat to the country's power supply is among their top fears.
Hackers have gained access to U.S. utilities' electronic control systems and in a few cases have "caused an impact," said Joseph M. Weiss, a Cupertino, Calif.-based computer security specialist with Kema Inc., a consulting firm focused on the energy industry. He said computer viruses and worms also have caused problems.
Weiss, a leading expert in control system security, said officials of the affected companies have described the instances at private conferences that he hosts and in confidential conversations but have not reported the intrusions publicly or to federal authorities. He said he agreed not to publicly disclose additional details and that the companies are fearful that releasing the information would hurt them financially and encourage more hacking.
Weiss said that "many utilities have not addressed control system cyber-security as comprehensively as physical security or cyber-security of business networks."
The vulnerability of the nation's electrical grid to computer attack has grown as power companies have transferred control of their electrical generation and distribution equipment from private, internal networks to supervisory control and data acquisition, or SCADA, systems that can be accessed through the Internet or by phone lines, according to consultants and government reports. That technology has led to greater efficiency because it allows workers to operate equipment remotely.
Other systems that feed information into SCADA or that operate utility equipment are vulnerable and have been largely overlooked by utilities, security consultants said.
Some utilities have made hacking into their SCADA systems relatively easy by continuing to use factory-set passwords that can be found in standard documentation available on the Internet, computer security consultants said.
The North American Electric Reliability Council, an industry-backed organization that sets voluntary standards for power companies, is drafting wide-ranging guidelines to replace more narrow, temporary precautions already on the books for guarding against a cyber-attack. But computer security specialists question whether those standards go far enough.