Every smartphone OS up for total destruction—iPhone, Windows Mobile, Symbian, Android and BlackBerry—made it through the competition unscathed. Not because they're inherently more secure. It's just because their puny processing power and memory make things like the 10-second Safari hack harder to do, even though the exploit is totally there.
Another reason is that every phone has a unique carrier and OS version situation, which made it harder for researchers to come with exploits—for instance, one crafted for the Storm, which wasn't in the competition, actually didn't work on the Bold. So the multiplicity of phones out there is actually a good thing security-wise, though it makes more monolithic platforms, like the iPhone a more attractive target—kinda like Windows' juggernaut-size makes it a bigger target for exploits than Mac or Linux. That said, I don't think the survival rate will be so great next year. [Computerworld via Slashdot]