Remember when we reported about the drastic increase in TOR usage a few weeks ago? Well, according to Tor Project members, they postulate that the increase was probably due to botnets.

"The fact is, with a growth curve like this one, there's basically no way that there's a new human behind each of these new Tor clients," Dingledine wrote in a blog post on Thursday.

"Since no large software or operating system vendors have come forward to tell us they just bundled Tor with all their users, that leaves me with one conclusion: somebody out there infected millions of computers and as part of their plan they installed Tor clients on them," he wrote.

Dingledine encourages all Tor users to upgrade to Tor 0.2.4, which introduces a new connection-handshaking method that uses fewer CPU resources.

"In parallel, it would be great if botnet researchers would identify the particular characteristics of the botnet and start looking at ways to shut it down (or at least get it off of Tor)," Dingledine says.