The Korean Information Security Agency (KISA), controlled by the state, said that the websites of several government departments like the National Assembly, the Ministry of National Defense, and the presidential office along with private companies, including Korean Exchange Bank and Shinhan Bank, were affected owing to unknown hackers' constant assaults that began on July 7, 2009.

Consequently, an investigation has started into the incidents. Officials at KISA said the initial investigation discovered that a lot of PCs were infected by a virus that instructed users to visit leading authorized Internet sites in South Korea.

Reportedly, the total number of websites affected by the hacking assaults counted to 25 of which 11 were domestic, KISA officials stated.

It is reported that the apparent DDoS (Distributed Denial-of Service) attacks began around 6:00 pm local time on July 7, 2009 and continued till next day despite the recovery of majority of the websites at around 10:00 pm on July 7, as per KISA.

Even as police have started a probe to find the culprit, there hasn't been any report of major damage till now. Moreover, the attackers might be located in North Korea or China, as per an unknown official's statement at the Office of the President.

Hwang Cheol-jeung, Senior Official at the Korea Communications Commission, stated that around 18,000 PCs were already infected, while the infection still continued without signs of receding, as reported by The New York Times on July 8, 2009. Meanwhile, the government has advised users to upgrade antivirus software on their computers to prevent any virus infection.

The security specialists state that the new attack resembles the one that hit the US government sites, when 14 leading websites in the US including those of the State Department, the White House, and the New York Stock Exchange were attacked in a similar way starting July 4, 2009.