FYI, if MSM often talks about "cyber attacks from China", it doesn't necessarily means that the actual attackers are chinese, or from China.
A lot of personal computers in China are still running Windows XP (54.79% in september 2013) which is maybe the less secured OS you can run on a computer today. Windows XP is filled with security flaws that hackers can exploit to turn your computer into a "zombie", part of a larger botnet group. That means that hackers can make your computer do stuff without your knowledge or your consent. Attackers can then use infected zombie PC to launch large scale attacks (DDoS) against specific targets, by flooding them with requests until the targeted computers don't have the necessary hardware ressources to handle the massive amount of requests.
So, the fact that a lot of chinese computers are still running Windows XP means that a lot of them are most likely infected with malware that turns them into zombies, allowing hackers to launch attacks from them.
_http://en.wikipedia.org/wiki/Botnet
_http://en.wikipedia.org/wiki/Denial-of-service_attack