Universal serial bus (USB) devices are evaluated for access according to characteristics including descriptors and ROM information. Descriptors are cross-references to historic descriptors known to be associated with malicious or approved USB devices. ROM information is analyzed to determine congruity of data. Device drivers and configuration files on the USB device are reviewed for indicators of compromise or threat and assigned a corresponding security score. Security actions are taken according to a security score assigned according to matching descriptors and analyzed ROM information.