Earlier this month Intel patched a 10-year old remote code execution bug in its CPUs but the Electronic Frontier Foundation warns the Active Management (AMT) module isn't the only security risk. The foundation warns the largely undocumented Management Engine of Intel's chips features more than just the AMT module and could pose a potential cyber security risk. And while AMT can be disabled, there's currently no method to deactivate the Management Engine on Intel CPUs:
Since 2008, most of Intel’s chipsets have contained a tiny homunculus computer called the “Management Engine” (ME). The ME is a largely undocumented master controller for your CPU: it works with system firmware during boot and has direct access to system memory, the screen, keyboard, and network. All of the code inside the ME is secret, signed, and tightly controlled by Intel. Last week, vulnerabilities in the Active Management (AMT) module in some Management Engines have caused lots of machines with Intel CPUs to be disastrously vulnerable to remote and local attackers. While AMT can be disabled, there is presently no way to disable or limit the Management Engine in general. Intel urgently needs to provide one.
This post will describe the nature of the vulnerabilities (thanks to Matthew Garrett for documenting them well), and the potential for similar bugs in the future. EFF believes that Intel needs to provide a minimum level of transparency and user control of the Management Engines inside our computers, in order to prevent this cybersecurity disaster from recurring. Unless that happens, we are concerned that it may not be appropriate to use Intel CPUs in many kinds of critical infrastructure systems.