Spam levels are returning to two-thirds of what they were before the McColo Corp. shutdown. The shutdown of a major web-hosting firm took many of the spam-sending botnets off the map. The lag between the initial decline and the subsequent rise is attributed to the time it took for the botnet owners to find a new ISP and bandwidth provider. The Asprox and Rustock botnets are back with a vengeance after having found new command and control.”]
Source: https://www.csoonline.com/article/2123456/spam-spikes-again-weeks-after-mccolo-shutdown.html