As the Korean peninsula flirts with supposed nuclear war, North Korea has been accused of launching cyber-attacks on banks and TV broadcasters in the south.
Investigators in Seoul said Pyongyang was behind the hacking of tens of thousands of computers last month.
Tension is already running high on the peninsula after North Korea, claiming to be angered by joint military exercises between the south and America, warned foreigners to leave before the start of a “thermonuclear war”.
The South Korean government has already warned there is a “high risk” that its crazed and dictatorial neighbour would launch a ballistic missile in the coming days, though no reputable analysts believe that the DPRK has yet managed to develop a nuclear warhead for its missiles.
The South Korean Ministry of Science, ICT and Future Planning said the cyber attacks were carried out by the Reconnaissance General Bureau, a North Korean intelligence agency rumoured to have set up a crack formation made up of thousands of cyber warfare top guns.
The ministry said:
“The attacker gained control of personal computers or server computers within the target organizations at least eight months ago.
“After maintaining monitoring activities, [the attackers] sent out the command to delete data stored in the server, and distributed malware to individual computers through the central server.”
In response to the news, the ministry announced plans to hold an emergency cyber security conference on Thursday.
The attack command came on 20 March, when the networks and websites of broadcasters KBS, MBC and YTN were crippled and brought offline. Three banks - Shinhan, Jeju and Nonghyup - were also attacked during the blitz, which struck some 48,000 machines. All three were forced to halt operations, although South Korea's Financial Services Commission insisted that no personal information or banking details were compromised.
Investigators traced the attack on the banks to six computers in North Korea, which had accessed the banks’ networks more than 1,590 times since June 2012.
Of the 76 malware samples recovered from the hacked computers, 30 had been used in previous attacks by the Democratic People's Republic of Korea. Researchers also found that 22 of the 49 IP addresses used during the attacks had previously been involved in similar incidents.
North Korea has already been blamed for an attempt to block access to the South Korean presidential website and hacks on the Korea Joongang newspaper and the Nonghyup bank.
One South Korean commentator warned that the more-developed southern nation's cyber-defences were insufficient to block North Korean attacks.
Writing in Korea Joongang, Chae In-taek said:
"South Korea cannot cope with unpredictable and sophisticated provocations from North Korea with a bureaucratic, rigid mindset.
"National security cannot be assured through an outdated system. We must come up with an innovative security system fast."
Although Kim Jong-un normally likes to broadcast videos of himself trying out the latest Nork military tech, Pyongyang has not yet commented on the cyberattack claims. ®