Reports have been circulating for a few weeks about a new attack being targeted at certain Windows users that used USB memory sticks to propagate. More details have now emerged, including confirmation from Microsoft that a new flaw exists and is being exploited.
The attack uses specially crafted shortcut (.lnk) files, which trick Windows into running code of an attacker's choosing. Any Windows application that tries to display the shortcut's icon—including Explorer—will cause exploitation, so even the mere act of browsing a directory with the malicious shortcuts is sufficient for a system to be exploited. Analysis suggests that the shortcuts are not improperly formed; rather they depend on a flaw in the way that Windows handles shortcuts to Control Panel icons.