As I commented elsewhere in this post, gossip is that the attack was launched from _within_ the Chinese offices of Google, not just from the Internet.
"Credible data describing the scope and impact of unwelcome insider actions are hard to come by..."
Shari Lawrence Pfleeger, Salvatore J. Stolfo, "Addressing the Insider Threat," IEEE Security and Privacy, vol. 7, no. 6, pp. 10-13, Nov./Dec. 2009, doi:10.1109/MSP.2009.146 http://www.computer.org/portal/web/csdl/doi/10.1109/MSP.2009...