Baidu, the company operating China's top Web search engine, is holding its domain registrar responsible for last week's security incident, resulting in downtime for its services. The Chinese firm filed a lawsuit in a New York court against U.S.-based Register.com.

For several hours on January 12, users who accessed Baidu.com were greeted by a Web page displaying the Iranian flag and a message from a group identifying itself as the "Iranian Cyber Army." It was later determined that the website itself was not compromised and that the defacement was the result of altered DNS records.

"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 company announced, according to AFP. A spokesperson for Baidu confirmed that the attack was possible "due to external manipulation of its DNS (Domain Name Server) in the United States."

It is worth noting that the same hacking group managed to hijack Twitter.com in a similar fashion back in December. It was later revealed that the compromised credentials of a Twitter employee were used to pull off the attack.

Baidu suggests it was different in its case by claiming that "gross negligence" on behalf of Register.com allowed attackers to unlawfully alter its primary domain's DNS records. The company refused to reveal any other details about the pending lawsuit at time.

According to Network World, when speaking about a recent high-profile cyber-attack against Google, a Chinese government official noted that indigenous companies are also victims and exemplified with the Baidu incident. "China is the biggest victim of hacking attacks," stressed Ma Zhaoxu, spokesperson for the country's Foreign Ministry.

Register.com is one of the Web's oldest and most reputed domain name registrars. It currently manages a number of over 2,5 million domain names and offers a series of related services, such as e-mail and Web hosting solutions.