With the expanding amounts of storage available on cell phones, mp3 players, digital cameras, and gaming devices it's no surprise that malware is increasingly being transmitted over USB. Avast Software is reporting that out of 700,000 attacks reported by its Community IQ system in October, one in eight were exchanged over USB connections. "Cyber-criminals are taking advantage of people's natural inclination to share with their friends and the growing memory capacity of USB devices," says Avast virus analyst Jan Sirmer.
One of the most common causes of USB malware transmittal is the Windows AutoRun feature. Typically left on by default, AutoRun scans newly connected devices and prompts the user for an action to take, from opening Office documents to playing video files. During this simple scan malware can infect a computer, turning a feature of convenience into a dangerous liability. And as USB drives are now found anywhere and everywhere computers are used, simply trading data between users can result in easily infected PCs.
Some easy ways to protect yourself include keeping USB devices disconnected until the PC and its anti-virus software have fully booted, making sure on-access malware scanning is enabled and running in the background, or simply disabling AutoRun altogether.