The report, from anti-spam company Frontbridge, reveals that spam levels recahced record highs in April, peaking at 94 percent of all email traffic. During the month the firm also noticed a major increase in virus-laden email, probably as a result of the prolific Sober virus which SC reported is back on the prowl.
"We're seeing new types of erratic behaviour that's leading us to believe that the profile of spam is changing," said Charles McColgan, chief technology officer at FrontBridge. "Our research is starting to show new types of message strains that very frequently change their content, limiting the effectiveness of more primitive filters."
But one industry watcher claims businesses are ready for such attacks.
"There's a lot more blocking at the gateway, routine blocking that stops traditional viruses from entering the network," said David Emm, senior technology consultant at antivirus company Kaspersky. "The non-savvy home user with his eat-as-much-as-you-like broadband is the one still getting infected."
According to Emm virus attacks in general are changing as a result of their more commercial nature.
"We're seeing less global outbreaks and more localised infection that are easier to manage and strip information from machines," he said. "Against businesses non-email worms traditionally have more success, like Sasser. But the only example of that we've seen this year is a Mytob outbreak in mid-April."