Mobile malware is a growing threat in the IoT, according to Nokia

Mobile malware infections increased 83% in the second half of 2016, according to fresh data from Nokia. But while phone viruses and other bugs are still far from a mass-market problem—so far, at least—malware is already becoming a challenge for the IoT.

The Finnish telecom gear vendor said the overall monthly smartphone infection rate averaged .9% in the second half of 2016, peaking in October with a rate of 1.35%. Smartphones accounted for 85% of mobile infections, while Windows and PC systems connected to mobile networks represented the remaining 15% of infections.

The overall monthly infection rate averaged 1.08% in the second half of last year, marking a 63% increase over the first half of the year. Android devices were responsible for 81% of mobile infections; only 4% were traced to iPhones or other mobile devices.

But while the rate of smartphone infections remains small, Nokia noted the increasing vulnerability of the Internet of Things as that market begins to mature beyond its infancy. IoT devices were targeted by Mirai, which was first noticed in August, and used in some major distributed denial of service (DDoS) attacks.

“Mobile IoT devices were compromised by the Mirai botnet and participated in the massive Mirai DDoS attacks in September and October,” Nokia wrote. “This Mirai incident illustrates how vulnerable the Internet of Things can be, and demonstrates that additional security requirements are necessary to protect it from attacks and exploitation. Measures must be put in place to ensure it is securely managed, has secure communications and is monitored for future breaches.”

Indeed, security is becoming a major challenge for the IoT as connectivity comes to a wide range of devices including cars. Gartner said last year that spending on IoT security would reach $348 million last year, climbing to $547 million in 2018.