Anti-Japanese Hostilities Move to the Internet

"They are not toying around," he said. "These attacks have given us a taste of what role computer systems might play in a real war, in Japan or anywhere."

Japanese officials say the number and severity of the attacks in recent months have climbed to record levels as anti-Japanese sentiment has soared not only in China but also in South Korea, where almost half the population gains access to the Internet via broadband cable networks.

In March, tensions between Japan and South Korea grew after Japan restated an old territorial claim to a group of small islands occupied by South Korea. The claim stoked bad feelings connected with Japan's occupation of the Korean Peninsula from 1910 to 1945.

Japanese authorities, who spoke anonymously because of the sensitivity of the issue, said they had little doubt that the recent series of attacks had come from China and South Korea. Internet security companies such as LAC have traced the attacks to locations in both countries.

But the authorities said the relative ease with which hackers can disguise attacks -- by routing the attacks through third nations, for example -- had made it difficult to lodge official protests.

There is no indication that the Chinese or South Korean governments sanctioned the attacks, which appeared to originate with computer-savvy youths and seasoned hackers in those countries, Japanese officials said. In addition, the Chinese government, as part of a broader attempt to quell anti-Japanese protests across China, has quietly moved to block public access to Web sites advocating cyber-attacks on Japan.

"We could provide them with the evidence, and they could easily throw it back at us and say, 'You have no proof someone in another country didn't route their attack through us,' " said one Japanese official dealing with the attacks. "The fact is, when you're dealing with crimes committed outside your borders, and by nations which aren't exactly eager to cooperate, it makes it difficult to bring cyber-criminals to justice."

Officials say most of the hacking incidents have taken the form of relatively simple attacks that overwhelm a given site with messages and other communications and slow its operation to a crawl. The majority of these attacks are believed to stem from China.

Wan Tao, 34, who is one of China's best-known hackers and maintains a popular Web site, said in a telephone interview that the cyber-war was at least partly precipitated by Japanese hacker attacks on Chinese Web sites. But he conceded that postings have gone up inside personal blogs and other Web sites in China advocating attacks against Japanese Web sites at specific dates and times.

Nishimoto, the security company executive, said the more sophisticated forms of cyber-warfare -- including computer viruses -- had been coming from South Korea. But South Korean officials deny any homegrown campaign against Japan, saying they have maintained strict policing and enforcement of Internet laws prohibiting hacking.

Chinese authorities have cracked down on anti-Japanese street protests in part because the protests were being organized through the Internet and cell phone messages that had become increasingly difficult for the government to control. They also have reportedly begun cracking down on cyber-attacks and have shut down some Web sites where anti-Japanese campaigns were posted.

Experts here say the attacks show that the anti-Japanese protests have touched a nerve among young, tech-savvy and nationalist Chinese and Koreans -- while failing to ignite serious passions among Japanese youth.

"The right-wingers and nationalists in Japan all tend to be middle-aged guys," Nishimoto said. "They are not very skilled on cyber-attacks. I think they'd have to hire someone to show them how to do it."

Researcher Jin Ling in Beijing contributed to this report.