A study of more than 500 million IoT device transactions in little over two weeks between December 15 and December 31, 2020 discovered a 700% increase in IoT malware over a previous study of pre-lockdown 2019. The study (PDF), conducted by Zscaler ThreatLabz, found Gafgyt and Mirai accounted for 97% of the IoT malware that Zscaler detected.

The volume and variety of IoT devices left running during lockdown is vast. 553 different device types from 212 manufacturers were identified. The most common categories, accounting for almost 65% of the total, were set-top boxes (29%), smart TVs (20%), and smart watches (20%). But there were also more esoteric devices: smart fridges and musical lamps, and of course Tesla and Honda cars.