The malware is called WireLurker, and it is quite impressive, if only for the fact that it is the first known malware that can infect an iOS device that hasn't been jailbroken. Early reports say that there could be hundreds of thousands of infected devices. The bug is transmitted over USB, which is why it has mostly been spread through the Maiyadi App Store in China which loads apps onto an iOS device via Mac OS. WireLurker is pretty dangerous too, because it will apps already on a device through binary file replacement and turn other programs into malware as well, without the need to download anything extra.
Researchers are saying that infected apps have been downloaded over 350,000 times. Researchers at Palo Alto Networks have put together software to help users detect if they are infected, but it is fairly easy to avoid (as are almost all mobile malware examples right now). Basically, don't use 3rd party app stores; don't use USB chargers from unknown sources; and, avoid using enterprise provisioning permissions to install unapproved software.
Do that, and you should be just fine.