China says hackers caused the massive Web outage in the country earlier this week, but industry observers point the finger at the Chinese government's rigid filtering system which likely malfunctioned.
Some 200 million to 600 million online users were estimated to have been affected by a "breach" on Tuesday afternoon, when many websites with top-level domains such as ".com", ".net", and ".org" were redirected to a blank webpage. Country-level addresses ending in ".cn" were unaffected in the outage, which lasted between three and eight hours.
The redirected webpage was operated by U.S. company Dynamic Internet Technology, which provides a software tool, called Freegate, that allows online users to access websites blocked by their governments. According to the company's website, its clients include The Epoch Times, a newspaper run by the Falun Gong religious group, which is banned in China, as well as Radio Free Asia and Human Rights In China.
This had led some to believe the outage was the result of a cyberattack. Indeed, the Chinese government later blamed hackers for the blackout.
"According to an analysis of available data the center has preliminarily concluded that this incident was caused by a cyberattack. The source of the attack is under further investigation," a statement from state-run National Computer Network Emergency Response Centre.
However, industry watchers including China's hacker communities expressed doubt that the outage was the result of a malicious attack.
"Our investigation shows very clearly that the domain name service exclusion happened at servers inside China," Xiao Qiang, an adjunct professor at the University of California, Berkeley, who is familiar with the Chinese government's Web filtering system. He told Reuters that an error made by the mainland's internet censors appeared to be the cause of the problem. "It all points to the Great Firewall. How that happened or why that happened, we're not sure," Xiao said.
Dynamic Internet Technology also dismissed suggestions it was responsible for any breach, pointing the finger at the government's filtering system, though it acknowledged it was the owner of the redirected web address. The company's president, Bill Xia, noted that the Chinese government tapped DNS "hijacking" tools as a way to block local access to certain websites. He suggested that this might have backfired.
Chinese media reports said local hacker communities also pointed to a likely malfunction, accidentally rerouting Web traffic to the blank webpage instead of the original intent of blocking the U.S. company's IP address.
"This is what happens when you try to break the internet for censorship because things are going to go wrong, and in catastrophic ways, that bring down the internet or make it unusable. This is censorship backfiring," Collin Anderson, a researcher on censorship who is affiliated to University of Pennsylvania, told the Washington Post.
The Chinese government just this week mandated that online users register with their real names before they are allowed to upload videos to local video websites, expanding further controls on the types of content posted online. In 2012, it ordered microbloggers or weibo users to register their accounts with their real names, and last year extended this requirement to include prepaid mobile Internet cards and fixed-line phone services.