More than one thousand Lexmark printers are connected to the Internet with no security. This is the same situation that leads to every IoT compromise and things like the Mirai botnet. Vendors make it simple to get their equipment up and running, but it takes a little more than plugging it in and turning it on. There is rarely a reason for a physical device like a printer to be accessible directly from the Internet. A firewall takes care of the basics and then make sure you change default passwords.”]
Source: https://securityaffairs.co/wordpress/66909/iot/1000-lexmark-printers-vulnerable.html