US denies cyber raid on North Korea in retaliation for Sony attack
The US government was not responsible for sustained electronic attacks that crippled North Korea's internet infrastructure last month, two senior US officials have said.
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 insisted 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 White House has already hit back at North Korea, in the form of new economic sanctions against the secretive country led by Kim Jong-un.