Chinese search engine sues US web firm over hacker attack

The announcement came one week after Google, which trails Baidu in market share in China, said it could abandon its Chinese search engine, and perhaps leave the country entirely, over cyberattacks and censorship.

"Today Baidu filed a lawsuit against its domain name registration service provider Register.com, Inc. in a US court in New York, seeking damages over the incident of Baidu's service interruption last week," the Chinese firm said.

Nasdaq-listed Baidu said its site went down for hours after the January 12 attack by a group identifying itself as the "Iranian Cyber Army", the name used by hackers who briefly shut down the Twitter microblogging site last month.

Baidu spokesman Victor Tseng said at the time that service had been interrupted "due to external manipulation of its DNS (Domain Name Server) in the United States".

In its statement Wednesday, Baidu said the software behind its domain name "was unlawfully and maliciously altered" as a result of the "gross negligence" of Register.com.

This led to "users from many places around the world being unable to access the Baidu website for a number of hours and causing serious damages to Baidu".

Register.com is a leading domain registration service that manages more than 2.5 million domain names, according to the company's website.

A Baidu spokeswoman said the company would not provide any further information on the lawsuit.

Baidu had 58.4 per cent of China's search engine market in the final quarter of last year, followed by 35.6 per cent for Google China, according to Internet research firm Analysys International.