Trust me, nothing is 100% secure if people want to create malware. Let's say WP gets 60% market share... by the next day, there will be 1'000'000'000'000'000'000'000'000 new pieces of malware for it. ID theft is such a lucrative black market, that many many many people will want to take a slice of that pie. They patch the security holes causing it... by the next day the malware count has doubled and to add to that, the outdated malware will be patched up. But there will be enthusiasts that like creating malware just to troll people. That will be visible on WP too. They don't care where it hits, to them it's just fun and games. So I believe Windows Phone does have malware. As does BBOS (both pre- and post-10), iOS, Android, Symbian, et al. Ubuntu will suffer the same problem should it get decent market share. What can be the most secure thing in the world, can always be beaten by someone willing to put in the effort.