After a very quiet summer, it seems that the spam bots have awakened. We recently noticed a spike in blacklistings; after checking the usual data sources, it seems the spike is widespread and indicative of one or more spambot networks getting back into action. The graph above is from the CBL (source: cbl.abuseat.org), which is one of the world’s better botnet blacklists.
Is this another “back to school special” as we have seen in previous years, where the spammers go to sleep over the summer, only to turn their machines back on in time for mom and dad to come home from vacation (and start buying pills)?
Still, despite the recent uptick, botnet spam volume is still well below the peak in early 2010, which was as much as 6 times higher than present volumes.