North Korea web woes might be US revenge

NORTH KOREA appeared to be under cyberattack yesterday, days after United States President Barack Obama pledged to respond to a devastating hack of Sony Pictures that the FBI says was carried out by the pariah state.

Internet links between North Korea and the outside world suffered severe disruption, preventing anybody with a North Korean internet address from going online. It came a day after North Korea threatened to strike targets, including the White House and Pentagon, should the US launch retaliatory action against it.

Yesterday, experts were asking whether an episode that began when Sony revealed that it had been hacked last month was about to escalate into an all-out cyberwar.

While North Korea’s internet infrastructure is extremely limited, experts said the interruptions were unusual, raising suspicions that the country was under attack.

‘‘I haven’t seen such a steady beat of routing instability and outages in [North Korea] before,’’ said Doug Madory, of Dyn Research, which tracks global internet connectivity.

‘‘Usually there are isolated blips, not continuous connectivity problems. I wouldn’t be surprised if they are absorbing some sort of attack,’’ he told North Korea Tech, a website that focuses on the ‘‘Hermit Kingdom’’.

North Korea’s internet collapse might not have been the result of an attack, but the timing will raise suspicions that an outside player – possibly the US or South Korea – launched a ‘‘demonstration strike’’ against the regime of Kim Jong-un.

South Korea said yesterday that its nuclear plant operator had been hacked, providing a sobering reminder of the stakes in a new era of cyberwarfare. Korea Hydro and Nuclear Power said only ‘‘non-critical’’ data was stolen, and that the country’s 23 atomic reactors were not at risk. However, it ran emergency drills to prepare workers for a hacking attack aimed at disabling control systems.

The Sony studio’s computers were hacked as it was about to release The Interview, a comedy depicting a fictional assassination attempt on a North Korean dictator.