The first time I saw details about the Tigon2, I came up with the idea that it could be used to make a back door, remote gdb stub or remote sniffer in the firmware. In this paper, I will explain a way to develop such firmware programs and also the associated security risks.
Hidden malicious circuits provide an attacker with a stealthy attack vector. As they occupy a layer below the entire software stack, malicious circuits can bypass traditional defensive techniques. Yet current work on trojan circuits considers only simple attacks against the hardware itself, and straightforward defenses. More complex designs that attack the software are unexplored, as are the countermeasures an attacker may take to bypass proposed defenses. (via fefe)
