A peer-to-peer (P2) botnet called FritzFrog has been actively breaching SSH servers since January. The botnet is a P2P botnet, meaning that it has greater resiliency than other types of botnets because control is decentralized and spread among all nodes. The most-infected countries are China, South Korea and the U.S. Victims include well-known universities in Europe, and a railway company; the most-in-depth of the botnet.
Source: https://threatpost.com/fritzfrog-botnet-millions-ssh-servers/158489/