Vive le code fermé, en effet!
>>Sources have told us in the past that anti-virus firms were obliged to share both source-code and virus samples prior to been allowing to trade in China. We've never been able to prove this and only mention it as an anecdote that's worth considering when thinking about the recent run of malware-powered cyber-espionage attacks, routinely blamed on China.
Not a smart hypothesis. How can the AV source code possession be helpful for attacks? An AV has a database, which has to be fed constantly with never-ending flow of newly discovered malware . AV gets outdated and useless if not updated regularly. AV is useless in the first place due to the failings of the OS it owes its very existence to.
Say, should some one get a hold of the infamous flashplayer's source code, please let us know why the heck it needs so much CPU to even download a video on pause. My guess is that a machine becomes a cell of some nice super cluster to run a NASA emulations or some protein structure heavy computations :).