Chinese ISPs Caught Injecting Ads And Malware In Their Network Traffic (thehackernews.com)
Chinese Internet Service Providers (ISPs) have been caught red-handed for injecting advertisements as well as malware through their network traffic. Three Israeli researchers uncovered that the major Chinese-based ISPs named China Telecom and China Unicom, two of Asia's largest network operators, have been engaged in an illegal practice of content injection in network traffic. Chinese ISPs had set up many proxy servers to pollute the client's network traffic not only with insignificant advertisements but also malware links, in some cases, inside the websites they visit. If an Internet user tries to access a domain that resides under these Chinese ISPs, the forged packet redirects the user's browser to parse the rogue network routes. As a result, the client's legitimate traffic will be redirected to malicious sites/ads, benefiting the ISPs.
I lived in China for a number of years, and this has been going on for a long time now (at least, with my ISP China Unicom). Absolute PITA, but that pretty much describes most online experiences in China (with the exception of Taobao, which is head and shoulders above Ebay).