McColo disconnection resulted in more spam?

An analysis conducted by Google showed that the volume of unsolicited mails increased to the levels unseen since November when host provider McColo was disconnected. The report revealed that spam volumes in the second half of March returned to pre-McColo takedown levels. Besides, according to the analysis based on the inboxes Google manages for more than 50,000 businesses and 15 million business users the growth rate during the first three months of 2009 stood for 1.2% per day which is the highest it's been since early 2008.

"It's difficult to ascertain exactly how spammers have rebuilt in the wake of McColo, but data suggests they're adopting new strategies to avoid a McColo-type takedown from occurring again," Amanda Kleha, a member of Google's security and archiving team, writes here. "Specifically, the recent upward trajectory of spam could indicate that spammers are building botnets that are more robust but send less volume – or at least that they haven't enabled their botnets to run at full capacity because they're wary of exposing a new ISP as a target."

In the mid-November last year upstream internet providers pulled the plug on McColo, which hosted the master control channels for some of the world's biggest and most notorious spam gangs. The disconnection came after complaints it was a conduit for junk email, phishing, and other types of online crime. And according to some estimates almost overnight the spam level reduced by 40%.

Nevertheless since that time the volumes of junk mails have been continuously increasing with web-filtering firm MessageLabs reporting that in January spam volumes were about 80 percent of pre-McColo takedown levels.

Source: The Register