UEFI Firmware Vulnerabilities can be Exploited to Gain Unauthorized Access and Control of Your Computer

The Unified Extensible Firmware Interface, or UEFI, is typically the lowest level of software that runs on a modern motherboard, helping to boot the system into a ready state for use. Intel has multiple technologies to help secure firmware against attacks, including Boot Guard and BIOS Guard. Boot Guard helps to protect a system against a firmware-based attack by first verifying that trusted UEFI firmware is booting on the platform. BIOS Guard provides hardware-assisted authentication and protection against BIOS recovery attacks.

Researchers at the MITRE discovered several vulnerabilities in Intel's EDK2 UEFI reference implementation. Since this reference implementation is used by numerous manufacturers as the basis for their UEFI firmware, many systems (not only those by Intel) are affected. If an attacker gains Admin rights on a Windows system (because of other vulnerabilities), the attacker can inject rootkits into the UEFI firmware on the motherboard due to the vulnerability described here.  The risk of the firmware vulnerabilities is that an attacker could potentially compromise a system and gain unauthorized access and control.

UEFI Firmware updates are very important, "Microsoft is now trying to figure out a way to configure unified UEFI updates for hardware, and they want to be able to let users update the UEFI Firmware as easily the operating system."

The good thing, is that motherboard vendors, including AMI, have issued UEFI BIOS firmware updates to address the flaws he discovered, and which enable the Intel hardware-level protections that come with modern CPUs.