The outages occurred just after US president Barack Obama promised that his administration would respond to the hacker break-in at Sony Pictures Entertainment.
The Obama administration has been deliberately coy about whether it caused North Korea’s outage, which affected all the nation’s internet connections starting on the weekend of December 20.
But the two officials acknowledged to the Associated Press that it was not a US operation.
It was not immediately clear even within the administration whether rogue hackers or other governments disrupted North Korea’s networks.
The networks are not considered especially robust since they rely on a single provider, China United Network Communications Group Co, the state-owned provider in neighbouring China. North Korea’s service was sporadic, starting on Saturday December 20, then collapsed entirely for nearly 10 hours two days later in what has remained an enduring whodunit.
“It looks more like the result of an infrastructure attack than an infrastructure failure,” said James Cowie, chief scientist at Dynamic Network Services of Manchester, New Hampshire, who studied the outages. “There’s nothing you can point to that says it has all the hallmarks of an attack by a nation state. It could have been anybody.”
The denial of US involvement was intended to convey how seriously the administration considers offensive cyber attacks.