Modern computer systems benefit from a plethora of peripheral devices that provide such features as removable data storage, wireless network connectivity, multimedia capabilities, high-speed data transfers, and other enhancements for the human-machine interface. The hardware and software industries have made sensible efforts in defining and refining specifications, standards, and APIs that support several types of peripheral devices while fostering new development, which might prove to be a new battleground for sophisticated attackers and defenders. I analyze how peripheral devices interact with the operating system and what threats that interaction poses