In this 50-minute presentation (video below) from black hat USA 2018, Christopher Domas discusses hardware backdoors in “some” x86 processors 😮 with special attention given to VIA C3 CPUs.
Thankfully he’s open-sourced all his research, including his presentation slides, white paper discussing the topic, and crucially a GitHub repo of the tools used to test his theories.
From the white paper,
Abstract—As the complexity of x86 processors grows unbounded, the realities of the hidden and unexpected behaviors of these chips become apparent. While micro-architectural vulnerabilities such as speculative execution side channels are unsettling, more powerful, unknown capabilities remain buried deeper still. Here, we finally demonstrate what everyone has long feared but never proven: there are hardware backdoors in some x86 processors, and they’re buried deeper than we ever imagined possible.
Watch: