For the 5th straight year, impersonator bots were the most active bad bots, making up 24.3 percent of all bot activity. Both cheap and effective, impersonator bots are most commonly used to launch DDoS attacks, including October’s attack against DNS provider Dyn .
Article Link: http://www.csoonline.com/article/3166589/internet/study-1-in-3-website-visitors-is-an-attack-bot.html#tk.rss_networksecurity