You can't directly compare this with Stuxnet. Security people (or rather, security people who analyse viruses and worms) discovered stuxnet because it was in th

You can't directly compare this with Stuxnet. Security people (or rather, security people who analyse viruses and worms) discovered stuxnet because it was in the wild. Security companies run honeypot machines set up to capture viruses so they can analyse them. Stuxnet was identified because they weren't discriminate enough with their targeting. It was only after stuxnet spread itself onto the wider internet that security researchers picked up on it and then thought "this is weird" when they looked at its behaviour. How do you suggest a third party security researcher could learn about data transfer between Apple's servers and the NSA's servers? Short of hacking into the system or an Apple/NSA employee whistleblowing, there's no way they could.