Two major operations against botnets have been carried out by agencies in Europe and the U.S. this week. The U.S. targeted a botnet which had infected more than 19 million IP addresses. The 911 S5 botnet was created by YunHe Wang, a Chinese national, who has now been arrested. Cybercriminals were able to use IP addresses purchased from 911 S5 to conceal their originating IP addresses and locations when committing offenses. This was likely the world’s largest botnet ever, infecting computers in over 200 countries. In Europe, Europol conducted its largest ever operation against botnets, dismantling multiple malware droppers and arresting their ringleaders. Europol says its “Operation Endgame” is ongoing and new actions will be made public soon.