The spike in Tor traffic is caused by a Mevade Botnet, that hides its Command-and-Control server in thenetwork. Researchers at Fox-IT firm found evidence that the spike in. Tor traffic was caused after the events related to disclosure of the PRISM surveillance program. Since August 19, 2013, there has been an impressive growth in the number of Tor users. No one knew who or what is responsible for this spontaneous growth of. Tor users on the Tor Network.
Source: https://thehackernews.com/2013/09/Mevade-Botnet-Tor-anonymizing-network.html