A denial-of-service (DoS), or distributed denial-of-service (DDoS), occurs when an attacker sends a massive number of simultaneous requests to a target server or website—overwhelming its resources and effectively making it unable to perform or respond to legitimate requests.

The DoS or DDoS is typically executed using thousands or hundred of thousands of compromised devices—or bots—harnessed collectively as a botnet. A command-and-control server, controlled by the attacker, instructs the compromised devices to send as many requests as possible to the target server or website. The combined traffic from tens or hundreds of thousands of infected devices cripples intended target.

An IoT DDoS is the same as a standard or traditional DoS or DDoS attack. The main difference is that rather than using a botnet comprised of PCs or managed devices like tablets or smartphones, the IoT DDoS leverages an IoT botnet comprised of thousands or hundreds of thousands of compromised IoT devices.

The massive volume of IoT devices connected on the internet, combined with the inherent security weakness of most IoT devices makes it relatively simple for attackers to amass an IoT botnet that can be used for IoT DDoS attacks.