CVE-2024-28903 is a vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) that involves a protection mechanism failure related to the Secure Boot security feature. Secure Boot is a critical security component designed to ensure that only trusted software is loaded during the system boot process, preventing unauthorized or malicious code from executing before the operating system loads. This vulnerability is classified under CWE-693, which pertains to protection mechanism failures, indicating that the intended security controls of Secure Boot can be bypassed under certain conditions. The CVSS 3.1 base score is 6.7 (medium severity), with the vector indicating that exploitation requires local access (AV:L), low attack complexity (AC:L), and high privileges (PR:H), but no user interaction (UI:N). The impact metrics show high confidentiality, integrity, and availability impacts (C:H/I:H/A:H), meaning a successful exploit could lead to full compromise of system security, including unauthorized code execution at boot, potential persistence of malware, and system disruption. The vulnerability does not currently have known exploits in the wild, and no patches have been linked yet, suggesting it is either newly discovered or not yet actively exploited. The vulnerability affects a legacy Windows 10 version (1809), which is still in use in some environments but is no longer the latest supported version. The bypass of Secure Boot could allow attackers with local high privileges to circumvent boot-time protections, potentially loading unsigned or malicious bootloaders or kernel drivers, undermining the system's root of trust and enabling persistent, stealthy attacks that are difficult to detect or remove.

For European organizations, the impact of this vulnerability can be significant, especially for those still operating legacy Windows 10 Version 1809 systems in critical infrastructure, government, or enterprise environments. The ability to bypass Secure Boot compromises the foundational security of the device, allowing attackers to install persistent malware that can survive OS reinstalls or evade endpoint detection. This can lead to data breaches, espionage, ransomware deployment, or sabotage of critical systems. Organizations relying on Secure Boot as a key security control for compliance or regulatory requirements may face increased risk of non-compliance and potential legal or financial repercussions. The requirement for local high privileges to exploit limits remote attack vectors but raises concerns about insider threats or attackers who have already gained elevated access. Given the high impact on confidentiality, integrity, and availability, successful exploitation could disrupt business operations, damage reputation, and cause significant recovery costs. The absence of known exploits currently provides a window for proactive mitigation before active exploitation emerges.

1. Upgrade and Patch: Organizations should prioritize upgrading systems from Windows 10 Version 1809 to a more recent, supported Windows version where this vulnerability is resolved. If patches become available from Microsoft, they should be applied promptly. 2. Restrict Local Privileges: Since exploitation requires high privileges locally, enforce strict access controls and minimize administrative privileges on endpoints. Use least privilege principles and monitor for privilege escalation attempts. 3. Enhance Endpoint Security: Deploy advanced endpoint detection and response (EDR) solutions capable of detecting anomalous bootloader or kernel driver modifications. 4. Secure Boot Configuration Review: Verify Secure Boot is enabled and properly configured in UEFI firmware settings to reduce attack surface. 5. Physical Security Controls: Limit physical access to devices, as local access is required for exploitation. 6. Monitor and Audit: Implement logging and monitoring for suspicious activities related to boot processes and firmware changes. 7. Incident Response Preparedness: Develop and test incident response plans for boot-level compromises, including recovery procedures that may require firmware re-flashing or hardware replacement. 8. User Awareness: Educate privileged users about the risks of this vulnerability and the importance of safeguarding credentials and access.