The severity of attacks matches the hike in volume. Over 60% of the worms detected could disable existing desktop security software and undermine traditional existing antivirus protection.
"The alarming prospect of IM threats that disable virus protection software is a wake-up call to enterprises to put additional protection for defence-in-depth," says Imlogic's chief technology officer Jon Sakoda.
IM threats pose a particular problem for traditional antivirus software because they mutate so fast. AOL is the most common victim of attack, attracting 66% of threats, followed by MSN with 33% and Yahoo! with just 1%. Companies can combat the risks by educating users not to click on a link attachment.