11 Old Microsoft-Signed Linux UEFI Shims Could Let Attackers Bypass Secure Boot

A critical vulnerability has been uncovered in 11 outdated Microsoft-signed UEFI applications, which can be exploited to bypass Secure Boot on systems utilizing the UEFI firmware standard. This vulnerability enables attackers to execute malicious code during the boot process, potentially leading to the deployment of UEFI bootkits or other types of malware. The affected applications, signed by Microsoft, can be abused to circumvent Secure Boot mechanisms, compromising the security of the system. An attacker can leverage one of these vulnerable applications to gain unauthorized access to the system, allowing for the installation of malicious software¹. This discovery has significant implications for system security, as it highlights the potential risks associated with outdated and vulnerable UEFI applications. The ability to bypass Secure Boot on most systems using the modern firmware standard poses a substantial threat to the integrity of the boot process, so a thorough review and update of UEFI applications is crucial to prevent such attacks.