CVE-2024-37981 is an integer underflow vulnerability classified under CWE-191 affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability specifically impacts the Secure Boot security feature, which is designed to ensure that only trusted software is loaded during the system boot process. An integer underflow occurs when an arithmetic operation causes a value to wrap around below its minimum representable value, potentially leading to unexpected behavior. In this case, the underflow can be exploited to bypass Secure Boot protections, undermining the system's trusted boot chain. The CVSS 3.1 base score is 8.0 (high severity), with an attack vector of adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), and requiring user interaction (UI:R). The scope is unchanged (S:U), but the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H), indicating that a successful exploit could lead to full system compromise. No patches or known exploits are currently available, but the vulnerability has been publicly disclosed and assigned a CVE ID. The vulnerability's presence in an older Windows 10 version that is still in use in many environments increases the risk of exploitation, especially in scenarios where Secure Boot is a critical security control.

For European organizations, the impact of CVE-2024-37981 is significant due to the potential to bypass Secure Boot, a foundational security mechanism that prevents unauthorized code execution during system startup. Successful exploitation could allow attackers to load malicious bootloaders or kernel-level malware, leading to persistent and stealthy compromises that are difficult to detect and remediate. This could result in data breaches, ransomware deployment, or disruption of critical services. Sectors such as government, finance, healthcare, and critical infrastructure are particularly vulnerable given their reliance on Windows 10 systems and the importance of maintaining system integrity. The requirement for user interaction and network adjacency somewhat limits the attack surface but does not eliminate risk, especially in environments with remote access or phishing threats. The lack of available patches means organizations must rely on compensating controls until updates are released.

1. Upgrade affected systems from Windows 10 Version 1809 to a supported and patched version of Windows 10 or Windows 11 to eliminate the vulnerability. 2. Enforce strict network segmentation and limit exposure of vulnerable systems to untrusted networks, especially adjacent network vectors. 3. Implement robust endpoint detection and response (EDR) solutions capable of monitoring Secure Boot status and detecting anomalous bootloader or kernel activity. 4. Educate users to recognize and avoid social engineering or phishing attempts that could trigger the required user interaction for exploitation. 5. Regularly audit Secure Boot configurations and ensure it is enabled and properly enforced on all systems. 6. Monitor security advisories from Microsoft for the release of patches or workarounds and apply them promptly. 7. Employ application allowlisting and integrity verification tools to detect unauthorized code execution during boot. 8. Maintain comprehensive backups and incident response plans to mitigate potential damage from exploitation.