Three flaws allow attackers to bypass UEFI Secure Boot feature

Researchers from hardware security firm Eclypsium have discovered a vulnerability in three signed third-party Unified Extensible Firmware Interface (UEFI) boot loaders that can be exploited to bypass the UEFI Secure Boot feature.

Secure Boot is a security feature of the latest Unified Extensible Firmware Interface (UEFI) 2.3.1 designed to detect tampering with boot loaders, key operating system files, and unauthorized option ROMs by validating their digital signatures. “Detections are blocked from running before they can attack or infect the system specification.” According to the experts, these three new bootloader vulnerabilities affect most of the devices released over the past 10 years, including x86-64 and ARM-based devices.

“These vulnerabilities could be used by an attacker to easily evade Secure Boot protections and compromise the integrity of the boot process;  enabling the attacker to modify the operating system as it loads, install backdoors, and disable operating system security controls.” reads the post published by the experts. “Much like our previous GRUB2 BootHole research, these new vulnerable bootloaders are signed by the Microsoft UEFI Third Party Certificate Authority. By default, this CA is trusted by virtually all traditional Windows and Linux-based systems such as laptops, desktops, servers, tablets, and all-in-one systems.”