The FBI says it has credible evidence to link the Chinese government to attackers who leveraged two Chinese telecom companies and the Baidu search engine to carry out recent distributed denial of service (DDoS) attacks targeting unnamed U.S. websites.
The FBI issued a confidential Flash Alert to U.S. companies alleging that the Chinese government sanctioned activities in which Internet traffic was “manipulated to create cyber attacks directed at U.S.-based websites” using man-in-the-middle (MitM) techniques.
“Analysis by the U.S. government indicated that Internet traffic which originated outside China, was intercepted and modified to make unsuspecting users send repeated requests to U.S.-based websites,” the Flash Alert reportedly said.
“The malicious activity occurred on China’s backbone Internet infrastructure, and temporarily disrupted all operations on the U.S.-based websites.”
Analysis of the attacks revealed that malware was injected into the browsers of users when web traffic reached China Unicom or China Telecom networks – both state-owned telecommunications companies – “at the same points in these routes that censor traffic for the Chinese government.”
“The location of the [man-in-the-middle] system on backbone networks operating censorship equipment indicates that the [man-in-the-middle] attack could not have occurred without some level of cooperation by the administrators of these systems,” the Alert said.
While the FBI Flash Alert did not specify which company’s websites were attacked, it is likely that the popular web-based software developers collaboration platform GitHub was among those targeted.
Researchers from the University of California at Berkeley, the University of Toronto, and Princeton recently published details of a powerful Chinese MitM tool dubbed the “Great Cannon,” which was used in DDoS attacks targeting websites operated by the anti-censorship project GreatFire.org, and later connected to the attacks on GitHub.
“Specifically, the Cannon manipulates the traffic of ‘bystander’ systems outside China, silently programming their browsers to create a massive DDoS attack,” the researchers said.
“The operational deployment of the Great Cannon represents a significant escalation in state-level information control: the normalization of widespread use of an attack tool to enforce censorship by weaponizing users.”
GitHub was likely targeted because GreatFire.org had begun to mirror some content on the platform. The attacks against GreatFire employed the same techniques as those seen in the GitHub attack, which leveraged hijacked Internet traffic.
This analysis aligns with details of the GreatFire.org attacks which was released previously.
“Millions of global internet users, visiting thousands of websites hosted inside and outside China, were randomly receiving malicious code which was used to launch cyber-attacks against GreatFire.org’s websites. Baidu’s Analytics code (h.js) was one of the files replaced by malicious code which triggered the attacks,” officials at GreatFire.org said.
“Baidu Analytics, akin to Google Analytics, is used by thousands of websites. Any visitor to any website using Baidu Analytics or other Baidu resources would have been exposed to the malicious code.”
GreatFire.org said it has conclusive evidence that the Chinese government using the nation’s infrastructure to conduct the attacks, and had previously published a detailed report, which was further backed up by the analysis provided by the university researchers.
“We show that, 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,” the researchers wrote.
“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, and can arbitrarily replace unencrypted content as a man-in-the-middle.”