Distributed denial-of-service (DDoS) attacks carried out by botnets continue to be a major threat to websites, although attacks on Windows systems are declining in favor of campaigns targeting Linux machines and Internet-of-things (IoT) devices, new NSFOCUS research shows.

The number of botnet attack instructions received by targets rose by 66.4% last year, with the vast majority of attacks targeting the United States (47.2%) and China (39.78%). The most popular targets of DDoS campaigns were gambling websites and porn websites. These websites were targeted an average of 79 times per day throughout 2018.

Read more: Botnets shift from Windows towards Linux and IoT platforms