Spam email spiked to its highest rate in over a year last month, accounting for 76.8 percent of all email in May, according to a new report from MessageLabs. That’s the biggest chunk of spam email since February of 2007, when spam levels were at 77.8 percent of all email.

Spam email increased by over three percent from April, with 1 in 1.3 emails being spam -- this after a slight decline, with spam at about 73 percent of emails in December of last year. Why the jump? Spammers are starting to ditch email attachments in favor of exploiting links to free hosted services like Google Docs, Calendar, and Microsoft SkyDrive, according to MessageLabs.

“The savvy, intelligent, and accurate cybercriminals of today seem to have abandoned the attachments tactic that was so innovative in late 2007 and are now focused on exploiting free hosted applications which have become mainstream in 2008,” says Mark Sunner, chief security analyst for MessageLabs in a prepared statement. “The spammers are taking advantage of the fact that these services are free, provide ample bandwidth, and are rarely blacklisted; this is one more addition to the growing list of ways the spammers have succeeded in outsmarting traditional detection devices.”

Spammers are basically looking for ways to evade filters, which for the most part don’t block links to Google Docs or Microsoft’s SkyDrive, according to the report. And MessageLabs says spammers are also tracking their spam performance via Google Analytics. According to the report, spammers insert a URL in an email that leads the victim to a Google Docs-hosted page. “In this way the spammer is actually creating what looks like spam content, not the full Website, but an advertisement for the Website they want the recipient to visit,” according to the report.

The most spammed country is still Hong Kong, with spam at 85.9 percent of all of its email. Spam in the U.S. reached 73.4 percent of all email last month.

— Kelly Jackson Higgins, Senior Editor, Dark Reading