Google said the downturn in spam following the takedown of the McColo server will soon be a distant memory, as spam levels recover to pre-McColo levels within a matter of months.
Last November, there was a 70 per cent drop in the world's spam when the McColo server was taken down, according to data taken from the Postini Message Security network. Although spam is still down overall, it is up by 156 per cent since the takedown - which shows that spammers have now recovered to fill the void.
Amanda Kleha of the Google Message Security Team compared 2008 levels with previous years, finding that spam threats rose visibly, reflecting an overall trend of rising attacks year on year.
She wrote on the Google Enterprise Blog: "Even with the drop in November 2008, spam levels climbed 25 per cent over 2007. Our statistics show that the average unprotected user would have received 45,000 spam messages in 2008, (up from 36,000 in 2007).
"All indicators suggest this trend will continue as virus, malware, and link-based attacks become more frequent and more ingenious."
Google looked ahead to 2009 and predicted that viruses sent via email and web attacks continue to be a serious problem. It also said that during the second half of 2008, virus volumes increased six-fold.
Attacks included the mimicking of package tracking notifications or invoices which contained virus attachments. There was also the problem of spoofed news alerts with URLs linking to websites hosting a virus.
