The number of new malware samples in the wild this year targeting connected internet-of-things (IoT) devices has already more than doubled last year’s total.

A white hat hacker is believed responsible for the Hajime IoT botnet because its main objective appears to be to secure IoT devices vulnerable to the notorious Mirai malware.

Attackers are targeting DSL routers this week with what’s being called a potent new variant of the Mirai malware that knocked offline major Internet companies like Twitter and Spotify last month.

Sierra Wireless warns that its AirLink gateways are being infected by the Mirai malware, and urges customers to change default passwords on devices.