Our team of Positive Technologies researchers has delved deep into the internal architecture of Intel Management Engine (ME) 11, revealing a mechanism that can disable Intel ME after hardware is initialized and the main processor starts. In this article, we describe how we discovered this undocumented mode and how it is connected with the U.S. government's High Assurance Platform (HAP) program.

[...] Intel Management Engine is a proprietary technology that consists of a microcontroller integrated into the Platform Controller Hub (PCH) chip and a set of built-in peripherals. The PCH carries almost all communication between the processor and external devices; therefore Intel ME has access to almost all data on the computer. The ability to execute third-party code on Intel ME would allow for a complete compromise of the platform.

[...] Unfortunately, analysis of Intel ME 11 was previously impossible because the executable modules are compressed by Huffman codes with unknown tables. Nonetheless, our research team (Dmitry Sklyarov, Mark Ermolov, and Maxim Goryachy) managed to recover these tables and created a utility for unpacking images. The utility is available on our GitHub page.