Great Cannon

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The Great Cannon of China is an Internet attack tool that is used to launch distributed denial-of-service attacks on websites by performing a man-in-the-middle attack on large amounts of web traffic and injecting code which causes the end-user's web browsers to flood traffic to targeted websites.[1] According to the researchers at the Citizen Lab, the International Computer Science Institute, and Princeton University's Center for Information Technology Policy, who coined the term, the Great Cannon hijacks foreign web traffic intended for Chinese websites and re-purposes them to flood targeted web servers with enormous amounts of traffic in an attempt to disrupt their operations. While it is co-located with the Great Firewall, the Great Cannon is "a separate offensive system, with different capabilities and design."[2]

Besides launching denial-of-service attacks, the tool is also capable of monitoring web traffic[3] and distributing malware in targeted attacks in ways that are similar to the Quantum Insert system used by the U.S. National Security Agency.[4]

Known uses[edit]

The first known targets of the Great Cannon (in late March 2015) were websites hosting censorship-evading tools, including GitHub, a web-based code hosting service, and GreatFire, a service monitoring blocked websites in China.[5]

In 2017, the Great Cannon was used to attack the Mingjing News website.[6]

As of December 2019, the Great Cannon was being used to attempt to take down the Hong Kong-based LIHKG online forum.[6]

See also[edit]


  1. ^ Perlroth, Nicole (April 10, 2015). "China Is Said to Use Powerful New Weapon to Censor Internet". The New York Times. The New York Times Company. Retrieved April 10, 2015.
  2. ^ Marczak, Bill; Weaver, Nicolas; Dalek, Jakub; Ensafi, Roya; Fifield, David; McKune, Sarah; Rey, Arn; Scott-Railton, John; Deibert, Ronald; Paxson, Vern (April 10, 2015). "China's Great Cannon". The Citizen Lab. Munk School of Global Affairs, University of Toronto, Canada. Retrieved April 10, 2015.
  3. ^ Franceschi-Bicchierai, Lorenzo (April 10, 2015). "The 'Great Cannon' is China's Powerful New Hacking Weapon". Motherboard - Vice. Vice Media LLC. Retrieved April 10, 2015.
  4. ^ Stone, Jeff (April 10, 2015). "China's 'Great Cannon' Lets Internet Censors Hack Sites Abroad -- Just Ask GitHub". International Business Times. IBT Media Inc. Retrieved April 10, 2015.
  5. ^ Peterson, Andrea (April 10, 2015). "China deploys new weapon for online censorship in form of 'Great Cannon'". The Washington Post. Retrieved April 10, 2015.
  6. ^ a b Doman, Chris (2019-12-04). "The "Great Cannon" has been deployed again". AT&T Cybersecurty blog. Retrieved 2019-12-06.