Defending Operating Systems from Malicious Peripherals

Modern peripherals are external devices that can connect with a computer system and provide extra functionality, such as keyboards, headsets, speakers, and smartphones. The connection is usually established via standard protocols, including USB, Bluetooth, and NFC. Modern operating systems implement these protocol stacks within the kernel and provide device drivers to serve different peripherals. Due to the current security model of "Trust-by-default", malicious peripherals can compromise the system after being connected even without the user noticing. In this talk, we review some highlights of peripheral attacks, such as BadUSB and BlueBorne attacks. We show how to build a generic security framework for all I/O subsystems within the Linux kernel to defend against malicious peripherals. We then formally verify the recent USB Type-C Authentication protocol and demonstrate why it is still challenging to authenticate a peripheral even with trust anchors. We conclude with how future work such as device fingerprinting can enable safer computing.