New telemetry on Internet of Things (IoT) devices demonstrates a dramatic increase in attacks on those devices during the work-from-home phase of the COVID-19 pandemic: There were some 300,000 attack attempts using IoT malware during a two-week period in December 2020.

The IoT malware, blocked by Zscaler, represented a 700% increase in activity against these devices compared with data gathered by the security firm before the pandemic. Nearly all of the IoT malware was the infamous Gafgyt and Mirai families, and more than 500 different types of IoT devices, including printers, digital signs, and smart TVs, were communicating with corporate IT networks when waves of employees were working from home amid the pandemic.

Nearly 60% of the attacks came out of China, followed by the US and India. Ireland (48%), the US (32%), and China (14%) suffered the most IoT attack attempts, and most attacks hit technology, manufacturing, retail, and healthcare organizations.

"For more than a year, most corporate offices have stood mostly abandoned as employees continued to work remotely during the COVID-19 pandemic. However, our service teams noted that despite a lack of employees, enterprise networks were still buzzing with IoT activity," Deepen Desai, CISO of Zscaler, said in a statement. More than three-quarters of IoT devices were communicating via unencrypted channels, "meaning that a majority of IoT transactions pose great risk to the business," he said.

The most targeted IoT devices were set-top boxes (29%), smart TVs (20%), and smartwatches (15%). Meanwhile, most of the risky IoT traffic came from manufacturing and retail devices, including 3D printers, barcode readers, and payment terminal devices.

Read the full report here, which includes IoT security recommendations.