https://www.cnet.com/news/we-cant-stop-botnet-attacks-alone-says-us-government-report/

Botnets -- they're not going away.

A newly released report from the departments of Homeland Security and Commerce takes a dive into the global cybersecurity issue. A botnet is a network of internet-connected devices that are infected with malware and controlled without the users' knowledge. They're used to launch things like distributed denial-of-service, or DDoS, attacks or ransomware attacks that can put critical infrastructure at risk, making them a big concern for the government.