North Korea's Internet has gone dark.
Industry and intelligence sources tell CBS News Justice and Homeland Security Correspondent Bob Orr that North Korean Internet has been "slow and spotty" for a couple of days and crashed completely at noon (ET) Monday.
It was unclear if the outage was the result of an attack, but some experts pointed to clues that it might have been. Doug Madory, the director of Internet analysis at Dyn Research, an Internet performance management company, said that access has been unstable since late Friday and that the sudden failure of the network is "consistent with a DDoS [distributed denial of service] attack on their routers."
A DDoS attack overwhelms an online service with traffic from multiple sources to make it unavailable.
The White House and the State Department declined to say whether the U.S. government was responsible, the Associated Press reported.
A senior administration official downplayed the possibility of a retaliatory cyber strike. Analyst Jim Lewis told CBS News trading shots in cyber space with North Korea is not a good option.
"We have a lot more to lose than they do," he said. "Turning out the lights in Pyongyang, they do that by themselves every day. Turn out the lights in New York or Washington, there is real economic harm."
The FBI officially pointed the finger at North Korea for perpetrating the massive breach on Sony Pictures that led to the leak of employees' personal information and a raft of embarrassing emails, took down computers and led to the canceling of the company's Christmas release of the movie "The Interview," which lampooned an assassination plot against North Korean leader Kim Jong Un.
President Obama said Friday that the U.S. would respond to the Sony hack, but did not say how.
The Digital Attack Map, a database of daily DDoS attacks launched around the world, did not show activity aimed at North Korea, though cyber warfare expert David Gewirtz told CBS News, "I'm doubting any attack would show up on the attack map because there's not that much to attack." North Korea's Internet infrastructure is weak and its bandwidth limited.
Gewirtz continued, "I would say it is certainly plausible that a DDoS was directed at North Korea because it's certainly easy enough to do with such a small target."