China's Internet on early Sunday morning suffered a major distributed denial of service (DDoS) attack that briefly disrupted and slowed access to sites in the .cn domain.
The DDoS attack was the largest in history against the domain servers for China's .cn ccTLD (country code top level domain), according to the China Internet Network Information Center (CNNIC), which administers the domain.
The first attack started Sunday around midnight Beijing time, and was then succeeded by a larger attack at 4 a.m, the CNNIC said in an Internet posting. A number of sites were affected, but Internet service to the sites had been gradually restored by 10 a.m. Sunday
It's unclear where the attack originated from or if it was still continuing. A CNNIC spokeswoman said on Monday it would update the public once more information was gathered. Chinese regulators have already launched unspecified measures to protect the domain system, while CNNIC has apologized for the disruption.
China has often been accused of launching DDoS attacks. In this year's first quarter, it was the top source country for DDoS attacks, according to security vendor Prolexic. The U.S. was ranked second.
DDoS attacks can commonly work by deploying armies of hacked computers to send traffic to a website, saturating it with data so that it becomes inaccessible to normal users.
China, however, has said its facing a surge of Trojan and botnet attacks against the country. Many of those attacks are coming from the U.S., South Korea and Germany. China has also denied the country sponsors hacking, despite claims brought by U.S. officials and security vendor Mandiant that its government actively conducts cyber-espionage.