Billions of Windows and Linux devices are vulnerable to cyberattacks stemming from a bug in the GRUB2 bootloader, researchers are warning.
GRUB2 (which stands for the GRand Unified Bootloader version 2) is the default bootloader for the majority of computing systems. Its job is to manage part of the start-up process – it either presents a menu and awaits user input, or automatically transfers control to an operating system kernel.
Secure Boot is an industry standard that ensures that a device boots using only trusted software. When a computer starts, the firmware checks the signatures of UEFI firmware drivers, EFI applications and the operating system. If the signatures are valid, the computer boots, and the firmware gives control to the operating system. According to Eclypsium researchers, the bug tracked as CVE-2020-10713 could allow attackers to get around these protections and execute arbitrary code during the boot-up process, even when Secure Boot is enabled and properly performing signature verification.