The Hong Kong-based China Human Rights Defenders said its Chinese-language website was inaccessible for several days after a series of distributed denial-of-service attacks last week and earlier this week. The attacks involve a host of computers seeking to connect to a website at the same time, overwhelming its server.
The group said its website and those of four other organizations promoting human rights in China were also attacked in late January at exactly the same time, apparently reflecting a coordinated assault.
The most recent denial-of-service attacks were “the worst such attacks in the site’s history,” China Human Rights Defenders said.
The group said it had not identified the source of the attacks but said they were “becoming an increasingly popular means of targeting websites operated by Chinese human rights activists.”
Also on Friday, the Foreign Correspondents’ Club of China said “persistent denial-of-service attacks” this week had forced it to suspend its website.
“We do not know who is behind these attacks or what their motivation is,” the club said in a statement.
“The attacks have come from IP addresses in both China and the US, but the physical location of the servers does not tell us much since hackers can use any machine they have been able to exploit,” it said.
More than 20 of the several hundred foreign journalists based in China have reported apparent phishing or hacking attacks against their Google or Yahoo e-mail accounts in recent weeks.
Last week, US internet giant Google Inc diverted its main Chinese website to an uncensored one in Hong Kong after its announcement in January that it would stop censoring its Chinese search results, as required by mainland authorities.
Google said its move was made after discovering cyberattacks that originated in China and targeted Google servers as well as those of other Western companies.
The attacks included attempts to compromise Chinese human rights activists’ e-mail accounts, Google said.
The Chinese government denied any involvement in the earlier attacks.