2009-04-01
Abstract
Spam volumes return to the same levels as those seen prior to the takedown of the McColo ISP.
Copyright © 2009 Virus Bulletin
Spam volumes have returned to the same levels as those seen prior to the takedown of the McColo ISP in November 2008.
Spam levels plummeted after the McColo ISP – which hosted botnet control centres that controlled zombies around the world, and which were responsible for more than 75% of the spam sent globally each day – was taken offline by its upstream providers. The ISP was blocked when evidence of suspicious activities on its network was presented to the upstream providers.
Although spam volumes started to rise again just two weeks after the web‑hosting firm was taken offline, it has taken four months for them to recover to the same heights.
According to Google, the seven-day average spam volume observed during the second half of March was the same as that seen prior to the blocking of McColo.
According to Google’s researchers, data suggests that spammers are adopting new strategies to avoid a similar takedown from occurring in the future – such as building botnets that are more robust but send smaller volumes of messages, or running botnets at less than their full capacity in order to stay under the radar.
