Stuxnet, Duqu and Flame are not normal, everyday malware, of course. All three of them were most likely developed by a Western intelligence agency as part of covert operations that weren't meant to be discovered. The fact that the malware evaded detection proves how well the attackers did their job.

Antivirus systems need to strike a balance between detecting all possible attacks without causing any false alarms. And while we try to improve on this all the time, there will never be a solution that is 100 percent perfect.

We want to detect malware, regardless of its source or purpose. Politics don't even enter the discussion, nor should they. Any malware, even targeted, can get out of hand and cause 'collateral damage' to machines that aren't the intended victim.

Mikko Hypponen Quotes