And given the general shift from old-school viruses that spread via infected files or removable media, the idea that the Mac population isn't sufficiently dense for malware to spread is no longer relevant.
So I talked to Michael Sentonas, McAfee's Chief Technology Officer for the Asia-Pacific region. "We are seeing more Mac OS X malware coming through [McAfee Labs]," he said., specifically code that co-opts systems into botnets, fake antivirus software, and banking Trojans (as well as more general password-stealing Trojans).
"Slowly we're seeing ports of the common malware" to Mac OS X and mobile platforms, he explained.
"It's so easy to port any code across to [iOS devices] so the risk exposure will become a lot greater over the next 18 months," added Sentonas. Jailbroken iOS devices present more fertile ground for attackers, but if there weren't any vulnerabilities in the platform jailbreaking wouldn't be possible.
He also suggested that the growing number of application stores for various platforms will have an effect. "We will start to see more malware that will target [specific] apps," he said, suggesting that users need to be less trusting.