"AutoRun is a really useful tool, but it is also a way to spread more than two-thirds of current malware," said Virus Lab analyst Jan Sirmer. Cyber-criminals are preying on people's natural inclination to share files with family, friends and coworkers via USB-attached memory, which is in handheld consoles, cell phones, digital cameras and portable music players.
Avast says its anti-virus software thwarted 84% of the USB/AutoRun related attacks with an on-access scan, while the remaining 16% were detected full drive scans. However, it was noted that detection rates could fall as storage devices grow in capacity. "A full scan can take up to an hour for a one terabyte device, so people will skip this entirely or just go for a quicker on-access scan." The firm offered a few pointers on keeping safe:
- Be aware. Around 60% of malware can now be spread via USB devices. This is an under-appreciated threat to home and business computers.
- Don't start attached. Turning on a PC with a USB device attached can result in malware being loaded directly to the computer ahead of some antivirus programs starting up.
- Scan first, look second. Make sure "on-access auto-scans" are enabled in in your antivirus program.