The infamous Rustock botnet, responsible for almost half of all spam sent last year, has suddenly slowed to a crawl. There’s no clear explanation for the decrease, which may be temporary. Rustock typically would send about 44.1 billion spams per day but that volume suddenly dropped on Dec. 25 to about 500 million per day. Other spam-producing botnets are suddenly going silent, including one called Lethic and Xarvester. Some believe it has roots in Russia.”]
Source: https://www.csoonline.com/article/2126601/spam-volumes-drop-as-rustock–other-botnets-go-quiet.html