Reboot your IoT Devices regularly!
https://www.ic3.gov/media/2018/180802.aspx
https://www.ic3.gov/media/2017/171017-1.aspx
“Reboot devices regularly, as most malware is stored in memory and removed upon a device reboot. It is important to do this regularly as many actors compete for the same pool of devices and use automated scripts to identify vulnerabilities and infect devices.”
https://www.us-cert.gov/ncas/tips/ST17-001
https://www.us-cert.gov/ncas/tips/ST17-001