China's New Weapon to Censor the Internet

[The Great Cannon] allows China to intercept foreign web traffic as it flows to Chinese websites, inject malicious code and repurpose the traffic as Beijing sees fit. The system was used, they said, to intercept web and advertising traffic intended for Baidu — China’s biggest search engine company — and fire it at GitHub, a popular site for programmers, and GreatFire.org, a nonprofit that runs mirror images of sites that are blocked inside China. — NY Times