A massive power failure this time of year could leave millions of us in the dark ... possibly for a long time. A blackout that would be all the worse if it were the result of a deliberate attack. Chip Reid reports our Cover Story:

When the lights go out, we usually know why: Mother Nature is at it again.

Most of the time we manage to get through it. But what if the power went out in a number of states affecting millions of people for weeks, even months?

As he was researching his new book about the nation's power grid, veteran journalist Ted Koppel said "frightened" was perhaps too strong a word, "but maybe I should have been."

Crown

In "Lights Out," Koppel paints a grim picture of a paralyzing power outage in the form of an all-out cyberattack on the nation's electrical grid.

"It's frightening," Koppel said. "I mean, it is frightening enough that my wife and I decided we were going to buy enough freeze-dried food for all of our kids and their kids."

"Who are the potential perpetrators here?" Reid asked. "Who do we have to fear the most? Is it Russia? China? Iran? Terrorists? Individual actors?"

"All those. The interesting thing, Chip, is the ones who are most capable are the ones least likely to do it.

"There are some experts who say they're already in."

"Well, they are in. There's no question about it. They are already in the grid. I was told that by the former Chief Scientist of NSA, he stated categorically the Russians are in, the Chinese are in. The Iranians may be on the verge of getting in. And then at the bottom of the capability scale are folks like ISIS, terrorist groups."

The power grid is the system interconnecting North America's supply of electricity. If one area has particularly heavy demand, power from another region can sometimes serve as back-up.

The downside to all this? If a hacker manages to take down an entire grid, a huge portion of the country -- along with parts of Canada -- could go down with it.

The primary reason? Like so much else these days, the grid relies heavily on the Internet.

Larry Pesce, a cyber security consultant, said, "We have sort of a joke in our security industry, that there's no secure system; the only secure one is unplugged, turned off and buried under concrete."

Pesce should know. He gets paid to find security glitches in business computer networks. In other words, he's a hacker who works for the good guys.

"In the last six years of me doing testing full-time, there has never been a customer that we have not gotten in," though some, he allowed, are easier to get into than others.

Wide-scale outages are nothing new. In 1965, a massive outage in the Northeast left more than 30 million without power for almost 13 hours. In 1977, New York City was plunged into darkness again, this time resulting in looting and other crimes.