The research, conducted by MessageLabs, also pointed out a slight decrease in the amount of viruses seen in email as well as a decline in phishing.
Last month, spam increased by 6.9 percent since May, accounting for nearly 65 percent of all emails scanned during the month. That total, however, was 7.8 percent below levels reached during June 2005.
Paul Wood, senior analyst with MessageLabs, said today that this convergence – as well as the short period of time it took for malicious users to achieve this – stood out.
"The thing that does surprise many is the speed at which this has occurred. If you look at viruses, it's taken maybe 16 years or so to get to this point. It's taken spyware three or four years to reach the same level of sophistication," he said. "It's becoming more difficult for IT managers to safeguard from these types of threats. You have to look at the whole picture and have defense of depth for the whole system."
June also saw a slight drop in the number of viruses in email traffic, decreasing 0.5 percent from last month to less than 1 percent.
However, MessageLabs did find a six-fold increase in the number of highly targeted trojan attacks designed to appropriate intellectual property from organizations.
Wood cautioned that that high increase was due to the relatively small number of targeted trojans.
Phishing attempts decreased by 0.12 percent from May levels, with one in 531 emails containing a phishing attempt, according to the study.
Mark Sunner, chief technology officer for MessageLabs, also said the convergence of different technologies to infect PCs with malware is a worrisome trend.
"The increased convergence of threats across email, web and IM combined with the increased sophistication of techniques is an interesting new development," he said. "Today, we see a growing number of emails and IMs containing links to websites where malware or spyware is automatically downloaded, as opposed to the traditional method where the message itself has a piece of malware attached."