China 'attacking websites across the globe in new censorship offensive'

China has expanded its internet censorship efforts beyond its borders with a new strategy that attacks websites across the globe, researchers said.

The new strategy, dubbed "Great Cannon," seeked to shut down websites and services aimed at helping the Chinese circumvent the "Great Firewall," according to a report by the Citizen Lab at the University of Toronto.

"While the attack infrastructure is co-located with the Great Firewall, the attack was carried out by a separate offensive system, with different capabilities and design, that we term the 'Great Cannon'," it said. "The Great Cannon is not simply an extension of the Great Firewall, but a distinct attack tool that hijacks traffic to (or presumably from) individual IP addresses."

The report supports claims by the activist organisation GreatFire, which last month claimed China was seeking to shut down its websites that offer "mirrored" content from blocked websites like those of the New York Times and others.

The technique involves hijacking internet traffic to the big Chinese search engine Baidu and using that in "denial of service" attacks which flood a website in an effort to knock it offline.

The report authors said the new tool represented "a significant escalation in state-level information control" by using "an attack tool to enforce censorship by weaponising users."

The Great Cannon manipulated the traffic of "bystander" systems including "any foreign computer that communicates with any China-based website not fully utilising (encryption)."