Drive-based threats may pose a larger risk to your business than drive-by attacks -- and USB drives may pose the largest threat of all.Threats carried by USB drives, and brought inside your network by employees -- either deliberately or, more likely, in complete ignorance of the risk -- continue to worsen.

Panda reported recently that malware launched from USB drives accounted for a quarter of SMB infections last year.

Big organizations are getting flash-drive slammed too, including the biggest of all -- a recently revealed 2008 attack on U.S. military networks was launched from a USB flash drive.

It's easy to see why the crooks are taking the USB route to your material. Flash drives are cheap, increasingly powerful and absurdly easy to use: plug in the drive and you're ready to go.

Unfortunately, with Auto-Run malware, the crooks are ready to go too.

The Pentagon's solution to its flash drive problem was to ban the drives for a year. Not a bad solution -- and one every business should consider, at least for as long as it takes to put into place a proper removable storage device policy and monitoring tools.

That policy should include:

Clear and straight forward delineations of what drives can and cannot be plugged into your system. In addition to flash drives, removable memory in cameras, phones, as well as music players and other USB devices should be included in the policy.

Auto-Run and Auto-Play should be disabled (although hackers are on the lookout for ways around even disabled auto-run features.

Under no circumstances should unfamiliar USB drives and devices be introduced into the network. Even if the drive comes from a seemingly reputable source, it can carry malware, as recipients of an infected IBM flash drive tchotchke learned to their dismay.

Finally, give some serious thought and budget consideration to implementing business-wide port and device monitoring. You and your security manager should know every time a device is introduced into a port, whether in compliance with your USB device policy or not.