The clock is ticking for Windows and Linux users to update cryptographic keys that protect their systems against firmware-based UEFI infections, a pernicious form of malware that loads before operating system and anti-malware protections start.
Beginning June 24, three certificates that cryptographically verify that each piece of firmware and software that loads during system boot will expire. The Microsoft-signed certificates are the linchpins of Secure Boot, a Microsoft-designed chain of trust. Secure Boot checks the digital signatures of all firmware that loads during system startup to ensure it originates from a trusted provider, such as the manufacturer of the motherboard the system runs on.
Secure Boot is designed to thwart UEFI bootkits, a form of malware that alters the Unified Extensible Firmware Interface, the successor to the BIOS, both of which begin the initial boot sequence. Because these bootkits load before the OS and most other code, they can be difficult to detect. Once installed, they typically load malware onto the OS that steals credentials, backdoors the system, or performs other malicious actions. Even when the OS is disinfected, the bootkit can reinfect the system. Bootkits survive OS reinstallations as well.
