SEOUL, South Korea (AP) — Suspected cyber attacks paralyzed Web sites of major South Korean government agencies, banks and Internet sites in a barrage that appeared linked to similar attacks in the U.S., South Korean officials said Wednesday.
The sites of 11 organizations including the presidential Blue House, the Defense Ministry, the National Assembly, Shinhan Bank, Korea Exchange Bank and top Internet portal Naver went down or had access problems since late Tuesday, said Ahn Jeong-eun, a spokeswoman at Korea Information Security Agency.
They appeared to be linked to the knockout of service of Web sites of several government agencies in the United States, though investigators are still unsure who was behind the attacks, Ahn said.
The U.S. sites were hit by a widespread and unusually resilient computer attack that began July 4, The Associated Press has learned.
In the United States, the Treasury Department, Secret Service, Federal Trade Commission and Transportation Department Web sites were all down at varying points over the U.S. Independence Day holiday weekend and into this week, according to officials inside and outside the government.
Others familiar with the U.S. outage, which is called a denial of service attack, said that the fact that the government Web sites were still being affected three days after it began signaled an unusually lengthy and sophisticated attack. The officials spoke on condition of anonymity because they were not authorized to speak on the matter.
An initial investigation in South Korea found that many personal computers were infected with a virus program ordering them to visit major official Web sites in South Korea and the U.S. at the same time, Korean information agency official Shin Hwa-su said. There has been no immediate reports of similar cyber attack in other Asian countries.
The National Intelligence Service — South Korea's main spy agency — said in a statement that 12,000 computers in South Korea and 8,000 computers overseas were infected and used for the service attack.
The agency said it believes the attack was "thoroughly" prepared and committed by "at the level of a certain organization or state." It said it is cooperating with the American investigative authorities to examine the case.
South Korea's Yonhap news agency said that military intelligence officers were looking at the possibility that the attack may have been committed by North Korean hackers and pro-North Korea forces in South Korea.
South Korea's Defense Ministry said it could not immediately confirm the report.
South Korean media reported in May that North Korea was running a cyber warfare unit that tries to hack into U.S. and South Korean military networks to gather confidential information and disrupt service.
Yang Moo-jin, a professor at Seoul's University of North Korean Studies, said he doubts whether the impoverished North has the capability to knock down the Web sites.
But Hong Hyun-ik, an analyst at the Sejong Institute think tank, said the attack could have been done by either North Korea or China, saying he "heard North Korea has been working hard to hack into" South Korean networks.
Yonhap said that prosecutors have found some of the cyber attacks on the South Korean sites were accessed from overseas. Yonhap, citing an unnamed prosecution official, said the cyber attack used a method common to Chinese hackers.
Prosecutors were not immediately available for comment.
Shin, the Information Security Agency official, said the initial probe had not yet uncovered evidence about where the cyber outages originated.
Police also said they also haven't found where the outages originated. Police officer Jeong Seok-hwa said that could take several days.
Some of the South Korean sites remained unstable or inaccessible on Wednesday. The site of the presidential Blue House could be accessed, but those for the Defense Ministry, the ruling Grand National Party and the National Assembly could not.
Ahn said there were no immediate reports of financial damage or leaking of confidential national information. The alleged attacks appeared aimed only at paralyzing Web sites, she said.
South Korea's Defense Ministry and Blue House said Wednesday that there has been no leak of any documents.
The paralysis took place because of denial of service attacks, in which floods of computers all try to connect to a single site at the same time, overwhelming the server that handles the traffic, the South Korean agency said in a statement.
The agency is investigating the case with police and prosecutors, said spokeswoman Ahn.
Associated Press writers Wanjin Park in Seoul and Lolita C. Baldor in Washington contributed to this report.
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