Spam volume was up 45% in the first half of January after diving in Q4 according to a Commtouch spam report. Reports show the recently dormant Waledac botnet has awakened, and is currently busy pushing out pharmaceuticals. Rustock, which inexplicably disappeared on December 25 and is the world s largest botnet, has made a resurgence as well. Spam levels are slightly lower than those before Christmas, but Symantec researchers speculate spam levels will return to what once were.
Source: https://threatpost.com/after-lull-botnets-back-business-011311/74847/