A hacker called The Janitor has created multiple versions of a program called BrickerBot, a system that searches out and bricks insecure IoT devices. A researcher named Pascal Geenens has followed the worm for a few weeks and has seen it pop up and essentially destroy infected webcams and other IoT devices.
The devices all used a Linux package called BusyBox and had exposed telnet-based interfaces with default passwords. These devices were easily exploited by the Mirai botnet, which essentially turned them into denial-of-service weapons.
BrickerBot finds these devices and renders them unusable. The first version attacked about a thousand devices and alternate versions attacked thousands more. It disabled the devices by formatting the internal memory.