It's not every day that I can tell you about malware on Apple gadgets, but there's a new one that's infected 75,000 phones so far.
It's called AdThief, and it works by hijacking ads you see on your smartphone - like those annoying ones that pop up in free game apps. It replaces some of the code in the ad with its own code to steal some of the advertising revenue.
Even if the malware is only able to squeeze one cent a day in ad revenue out of 10% of its victims, that nevertheless comes out at a very handy $30,000 per year.
Most iPhone users don't have to worry. Apple is very strict about what you can and can't download on your gadget - that's why we don't see a lot of viruses on them. So, AdThief can only infect "jailbroken" phones.
Jailbreaking is where you go out of your way to remove Apple's security controls (ironically, usually by exploiting a security vulnerability) in order to win the freedom to do what you like with your iPhone or iPad.
Jailbreaking is tempting for some people because it lets you do even more with your gadget, like remove features you don't want and add apps not supported by Apple. But, it's dangerous too, because it removes all of Apple's security features that are there to keep bad apps out. So, you shouldn't do it. This isn't the first malware that's attacked jailbroken iPhones.