14 DAY TRIAL // Symantec's MessageLabs division reports that spam volume has decreased in March by two percent following the takedown of the Rustock botnet, but warns that Bagle is taking its place.
In its monthly intelligence report [pdf], the Symantec researchers point out that last month 83.1% of the global spam traffic was generated by botnets, which is lower than the 2010 average rate of 88.2%.
The Rustock botnet which was taken down in mid-March by Microsoft and other security companies, was responsible for 28.5% of the total.
Immediately after the takedown global spam volumes plummeted by 24.7%, followed by another 11.9% a few days later, leading to a total decrease of one third.
However, this will probably be short lived because other botnets will take on Rustock's business and increase their output.
In fact, this is already happening with Bagle, a botnet whose spam voulme is at its all time high and accounts 17.2% of the total.
"In March, spam output from Bagle has been at its highest since 2009, when at its previous peak in October of that year it accounted for approximately 12.2% of global spam. Notably, Bagle did not appear in the top ten spam-sending botnets at the end of 2010, as reported in the MessageLabs Intelligence 2010 Annual Security Report," the researchers write.
Bagle is mostly pushing pharma spam, but it is more impressive than Rustock because it manages to achieve more with less infected machines.
The size of Bagle is estimated to be between 180,000 and 280,000 computers and it pumps out 8.31 billion spam emails daily. Rustock's size was between 470,000 and 690,000 and generated 13.82 billion daily junk mails.
In terms of spam origin for this month, the Russian Federation is in first place with 12.4% of global traffic and is followed by India with 8.8%, Brazil with 5.9% and the United States with 4.5%.