CVE-2024-37974 is a vulnerability classified under CWE-191 (Integer Underflow) affecting Microsoft Windows 10 Version 1809 (build 17763.0). The vulnerability specifically targets the Secure Boot security feature, which is designed to ensure that only trusted software is loaded during the boot process. An integer underflow occurs when an arithmetic operation causes a value to wrap around below its minimum representable value, potentially leading to incorrect calculations or logic errors. In this case, the underflow can be exploited to bypass Secure Boot protections, undermining the system's trust chain and allowing an attacker to execute unauthorized code early in the boot process. The CVSS v3.1 score of 8.0 indicates high severity, with an attack vector of adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The scope is unchanged (S:U), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). No known exploits have been reported in the wild yet, but the vulnerability's nature and impact make it a critical concern for affected systems. The lack of available patches at the time of publication means organizations must prioritize mitigation strategies to reduce exposure. This vulnerability is particularly critical because Secure Boot is a foundational security control that prevents unauthorized firmware, bootloaders, and OS loaders from running, thus protecting against rootkits and bootkits.

The impact of CVE-2024-37974 on European organizations is significant due to the potential for attackers to bypass Secure Boot protections, leading to full system compromise. This can result in unauthorized code execution at the earliest stage of system startup, allowing attackers to install persistent malware that is difficult to detect or remove. Confidentiality is at risk as attackers could access sensitive data; integrity is compromised as system files and boot components can be altered; availability is threatened if attackers disrupt system startup or cause system instability. Organizations in critical infrastructure, government, finance, and healthcare sectors are particularly vulnerable due to the sensitivity of their data and the importance of system availability. The requirement for user interaction may limit mass exploitation but targeted attacks against high-value European entities remain a concern. The lack of patches increases the window of exposure, especially for organizations that have not upgraded from Windows 10 Version 1809, which is out of mainstream support. This vulnerability could also facilitate supply chain attacks or lateral movement within networks once initial access is gained.

European organizations should immediately assess their inventory to identify systems running Windows 10 Version 1809 (build 17763.0). Since no patches are currently available, the primary mitigation is to upgrade affected systems to a supported and patched Windows version where this vulnerability is resolved. Organizations should enforce strict policies to prevent the use of outdated operating systems, especially on critical endpoints and servers. Additionally, organizations should enable and enforce Secure Boot policies with hardware root of trust and consider using additional endpoint detection and response (EDR) solutions that monitor boot integrity. User education is important to reduce the risk of social engineering that could trigger the required user interaction for exploitation. Network segmentation and limiting access to systems with vulnerable versions can reduce attack surface. Monitoring for unusual boot-time activity and firmware changes can help detect exploitation attempts. Finally, organizations should stay alert for Microsoft’s security advisories and apply patches as soon as they become available.