Baidu, China’s biggest search engine, has filed a lawsuit in New York this week, claiming that domain service failed to adequately protect its servers from a recent attack by a group calling itself the "Iranian Cyber Army."

CNET reports that Baidu’s suit alleges "gross negligence" on the part of, resulting in the search site being "unlawfully and maliciously altered." CNET also said that the company’s site for use within China was not affected by the attack, meaning that search engine optimization (SEO) within the mainland was unchanged.

Baidu’s homepage was defaced on January 12 for roughly four hours. The hacked page displayed bright red text taking credit for the attack, several lines of religious text in Arabic, and anti-U.S. propaganda in broken English. A similar attack last month affected microblogging site Twitter.

The lawsuit was filed in the midst of a related uproar over a recent cyber attack on U.S. search giant Google, in which the Chinese government has been implicated among the perpetrators. This has led Google to threaten a complete withdrawal from the country.