North Korea suspected of mounting cyberattack that shuts down South Korean banks, TV stations

SEOUL, South Korea — A possible cyberattack has shut down South Korean banks and TV stations with suspicions falling on North Korea after an escalation of rhetoric between Seoul and Pyongyang.

Screens went blank at 2 p.m. local time and skulls popped up on the screens, indicating a breach by hackers, the Associated Press wrote, citing the state-run Korea Information Security Agency.

TV stations KBS and MBC and cable channel YTN and two major banks, Shinhan Bank and Nonghyup, were paralyzed, according to reports.

The government, military and nuclear power plants appear to have been spared, The New York Times wrote.

South Korea's Defense Minister Kim Kwan-jin called an emergency security meeting to review the military's five-tier threat level system, designed to defend against a cyberattack, from Level 4 to Level 3, Yonhap wrote.

A ministry spokesman said:

Currently, the military network is operating normally. There were no [hacking] attempts from outside.

While the National Intelligence Service was still investigating the outage and was yet to find any evidence of external attacks, speculation in local media was that North Korea had fired the last salvo in a tit-for-tat exchange in a cyber war.

GlobalPost senior correspondent in Korea, Geoffrey Cain, says that "North Korea employs cyber-attacks — as opposed to their braggadocio of nuclear bombardments — because hacking is cheap and deniable."

"Pyongyang is actually home to all sorts of skilled techno-geeks trained by a regime that, in Kim Jong Un's words, upholds technology as one of the pillars of national development," Cain reported from Seoul.

"North Korean universities are always churning out computer specialists who, while working on civilian projects, are also adept at launching military-run computer operations against foreign countries," Cain said, adding:

Plus, given the latest war rhetoric, it's highly likely that North Korea was behind the latest computer attacks, perhaps to find some way to back up its words last week with action — even if that action is prosaic.

North Korea has been ratcheting up war rhetoric in response to the UN Security Council's adoption of new sanctions for the country's Feb. 12 nuke test.

Last week, North Korea accused South Korea and the US of attacking its state websites, including the Korean Central News Agency (KCNA) website and those of state newspaper the Rodong Sinmun and national airline Air Koryo.

More from GlobalPost: North Korea blames US, South Korea for 'intensive' cyberattacks

Cain said at the time that there was no way to know for sure whether KCNA is telling the truth that American cyber-militants tried to bring down North Korean servers.

"But the biggest irony is that, of all regimes, North Korea is the one making a fuss about hacking," Cain said from Seoul.

Later, North Korea threatened US island bases in the Pacific Ocean, NBC News reported.

According to the state-run Korean Central News Agency, North Korea would attack American bases if its "enemies … make even the slightest movement,” according to NBC.

Quoting Kim Jong Un, KCNA also suggested the presence of a US bomber in the area is further provocation to war.

“(Kim) continued that time has gone when only words were made, stressing the need to destroy the enemies without mercy so that not a single man can survive to sign a document of surrender when a battle starts,” the news agency said, according to NBC.

The North also trumpeted the successful test of its military might in shooting down a cruise missile during exercises, Reuters reported.

KCNA also said Kim supervised a successful "drone attack," although there's no proof North Korea possesses drones, Reuters said. 

Geoffrey Cain contributed to this report from Seoul.