PandaLabs security researchers report 25 percent of new worms discovered this year have been specifically designed to spread through USB storage devices, which includes flash drives, external hard disks, cell phones, portable media players, etc.
This distribution technique is highly effective. With survey responses from more than 10,470 companies across 20 countries, it was revealed that approximately 48 percent of SMBs (with up to 1,000 computers) admit to having been infected by some type of malware over the last year. As further proof, 27 percent confirmed that the source of the infection was a USB device connected to a computer.
So far, these types of infections are still outnumbered by those that spread via email, but it is a growing trend. "There are now so many devices on the market that can be connected via USB to a computer: digital cameras, cell phones, MP3 or MP4 players," says Luis Corrons, Technical Director of PandaLabs. "This is clearly very convenient for users, but since all these devices have memory cards or internal memory, it is feasible that your cell phone could be carrying a virus without your knowledge."