MessageLabs warned that malicious users will increasingly target IM in the next year, calling it a "widening backdoor" to infect enterprises with spam and trojan attacks.
"Spammers will diversify further into the IM ecosystems, as business adoption of IM increases and as the 'big three' IM protocols begin to standardize in 2006 and onwards," the company said. "Cybercriminals will seek to capitalize on this opportunity, as IM presents an increasingly attractive criminal gateway into the enterprise."
The company's year-end report also noted a considerable increase in phishing emails sent this year. Phishing represented 13 percent of malicious emails intercepted by the company during 2005, with a high of as much as 27 percent in January. In total, more than 62.5 million phishing emails were intercepted by MessageLabs since Jan. 1, a remarkable increase of 238 percent from the 18 million caught the year before.
The company also predicted more attacks on mobile devices: "Criminals will continue to attempt to gain access to users' mobile devices as the proliferation of wireless technologies like Wi-Fi spreads to airplanes, trains and other public locations. They will seek to exploit user ignorance and low levels of mobile device security countermeasures to gain covert access to enterprises."
The report said analysts found targeted attacks on specific industries became more common in 2005. Over all, MessageLabs reported one in every 36.15 emails sent this year contained a virus or trojan.
Mark Sunner, chief technology officer for MessageLabs, said cybercriminals chose more specific targets during 2005.
"2005 will be remembered as the year when messaging security risks shifted from mass random attacks to more highly designed, targeted threats," he said. "In the run-up to the holiday season, we have seen an increase in trojan and botnet activity, which has resulted in a wave of holiday phishing and spam. This is evidence of a concerted effort by the scammers to steal personal and business data."