Two of the world's largest bot networks were shut down in a major international operation, authorities announced on Friday.
German, US and Canadian cybercrime specialists joined forces to dismantle Aisuru and Kimwolf, suspected of being behind major online attacks.
They "posed a significant threat to IT infrastructure due to their size and associated attack capacitym," said German police, prosecutors and cybercrime officials.
A botnet is a network of computers or connected devices that have been infected with malware and are controlled secretly by an operator, who uses them for malicious purposes like attacks or data theft.
Aisuru consisted of a network of several million compromised online devices, such as routers and webcams, according to a statement.
The second, associated Kimwolf botnet involved several million infected devices, primarily Android TV boxes.
Two suspected administrators of the networks have been identified and now face "legal consequences," the statement said, without giving further details.
The botnets launched so-called "distributed denial of service attacks," where an operator floods compromised devices with massive amounts of traffic to slow them down or cripple them entirely.
They carried out "record-breaking attacks," according to the US Department of Justice, which was involved in the operation.
Infected devices were "enslaved" by the botnet operators, who then sold access to the compromised devices to other cyber criminals, the US officials said.
The cyber criminals extorted their victims, who in some cases suffered losses of tens of thousands of dollars, they said.
