DEF CON Safe Mode - Christopher Wade - Beyond Root

Rooting a smartphone is often considered the ultimate method to allow a user to take complete control of their device. Despite this, many smartphones contain hardware which is closed off to any modification. This talk aims to show how this hardware can be reverse engineered in order to bypass its protections and further expand its functionality. Using proprietary NFC Controllers as an example, we will cover analysis of the protocols used by the chips, how the firmware protections could be broken, and how custom firmware could be developed and deployed to the phone with no hardware modifications. This will include methodologies for analyzing weaknesses in firmware update protocols, leveraging the Unicorn CPU Emulator to bypass debugging restrictions, and techniques for reverse engineering the hardware capabilities of an unknown chip in order to implement custom features. This will end with demonstration of a smartphone with passive NFC sniffing capabilities and expanded tag emulation functionality.