Smartphones are now more dangerous than Windows laptops and PCs, with new research from Nokia revealing handsets account for 60 percent of malware in the mobile space.
Malware on Android handsets has doubled during the last six months of 2015, with the operating system still the most targeted.
Ransomware, previously only seen on PCs, is seen as one of the rising threats to smartphone users. It works by encrypting data and then locking it, effectively holding a user's device to ransom. The device can be unlocked after a user buys a voucher or pays up via Bitcoin.
However, the vendor's Threat Intelligence Lab also noted that iOS-based malware appeared in the top 20 threats for the first time, through XcodeGhost and FlexiSpy. In October, six percent of total infections was iPhone malware.
XcodeGhost malware originated in a compromised software development kit that was used by Chinese developers to build legitimate apps. While Apple has since removed the offending apps from the app store, some malware remains active.
There was better news for PCs connected to a mobile network. Because of a decrease in adware, the overall infection rate dropped from 0.75 percent to 0.49 percent in the second half of 2015.
Kevin McNamee, Head of the Nokia Threat Intelligence Lab, said: "Security is a very real concern for any device with an IP address, be it Android, iPhone or even a Windows PC connected to the mobile network. While Android infections continue to rise and become more sophisticated, the Nokia Threat Intelligence Report from late 2015 was the first time we saw iOS malware make our top 20 list, with XcodeGhost being the fourth most prevalent malware detected.
"We also saw a rise in a variety of ransomware apps that try to extort money by claiming to have encrypted the phone's data. Nokia's security approach reaches into the network to stop malware before getting to the device itself and before damage can occur."