The computer networks of South Korean broadcasters
and banks were paralysed Wednesday, prompting a police investigation
of a suspected cyberattack from abroad.
The computer failures prompted immediate speculation of a hacking attack from communist neighbour North Korea.
The cause of the network shutdowns was under investigation and whether North Korea was behind them remained undetermined, a police spokesman said.
The communications regulator, the Korean Communications Commission, said hacking of an unknown origin was suspected as the cyberalert level was raised to level three on a five-level scale.
Broadcasters KBS, MBC and YTN as well as Shinhan, Nonghyup and Jeju banks and two insurance companies reported that their computers froze about 2 pm (0500 GMT), the Yonhap News Agency reported, citing police.
Woori Bank came under an apparent hacking attack at the same time but it was able to defend its networks, Yonhap said.
KBS said programme production continued largely as usual but its access to the internet was blocked for hours.
The South Korean military, meanwhile, upgraded its surveillance of the country's information systems, Yonhap reported.
South Korea has accused the North of a series of cyberattacks on government and financial websites in recent years. Pyongyang has denied the charges and recently accused Seoul and Washington of attacking its computer networks.
Tensions have been high on the Korean Peninsula since North Korea conducted its third nuclear test in February, which was followed by a tightening of international sanctions against Pyongyang.
North Korea has also issued threats against the South and its ally the United States, who started joint military drills around the peninsula this month.
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