Description

Microsoft recently uncovered 20 previously unknown security vulnerabilities in the GRUB2, U-Boot, and Barebox bootloaders using its AI-powered Security Copilot. GRUB2 is widely used in Linux distributions, while U-Boot and Barebox are common in embedded and IoT devices. Among the discovered flaws, 11 vulnerabilities in GRUB2 involve integer overflows, buffer overflows, and cryptographic side-channel attacks. Additionally, 9 buffer overflow vulnerabilities were found in U-Boot and Barebox, primarily in filesystem parsing. These flaws could allow attackers to bypass UEFI Secure Boot and execute arbitrary code under certain conditions, potentially leading to bootkits that persist beyond OS reinstalls. These vulnerabilities pose significant security risks, especially in GRUB2, where attackers could exploit them remotely to bypass Secure Boot and compromise security mechanisms like BitLocker. Although U-Boot and Barebox need direct physical access for exploitation, it is well-documented that bootkits, including BlackLotus, have successfully been deployed as malware infections. Installation of persistent malware that outlasts disk replacements makes such vulnerabilities especially pernicious. Microsoft's Security Copilot helped to automate vulnerability discovery, minimizing the effort by a large degree and accelerating discovery of similar weaknesses in related projects. To mitigate these threats, affected users should update GRUB2, U-Boot, and Barebox to the latest patched versions, released in February 2025. Organizations should enable Secure Boot, regularly audit bootloader configurations, and monitor for unauthorized firmware changes. Security teams should also implement robust endpoint protection to detect potential bootkit infections. As AI-driven security tools continue to advance, they offer promising solutions to proactively identify and remediate vulnerabilities in complex codebases.