CVE-2024-28923 is a security vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) that involves an integer overflow or wraparound issue (CWE-190) within the Secure Boot security feature. Secure Boot is a critical security mechanism designed to ensure that only trusted software is loaded during the system boot process, preventing unauthorized or malicious code from executing early in the boot sequence. The integer overflow flaw can lead to a bypass of this security feature, potentially allowing an attacker with elevated privileges to circumvent Secure Boot protections. The vulnerability requires high privileges (PR:H) and local access (AV:L), with no user interaction needed (UI:N). The attack complexity is high (AC:H), indicating exploitation is non-trivial and likely requires detailed knowledge of the system internals. The vulnerability impacts confidentiality, integrity, and availability (all rated high), as bypassing Secure Boot could enable persistent malware installation, rootkits, or unauthorized code execution that compromises system trustworthiness. Although no known exploits are currently reported in the wild, the vulnerability is publicly disclosed and rated with a CVSS 3.1 score of 6.4 (medium severity). No patches or mitigations have been linked yet, emphasizing the need for vigilance and proactive defense measures. The flaw affects a legacy Windows 10 version (1809), which is still in use in some environments but has been superseded by newer releases. This vulnerability highlights the risks associated with outdated operating systems and the criticality of Secure Boot as a foundational security control in modern endpoint protection.

For European organizations, the impact of this vulnerability could be significant, especially in sectors relying on legacy Windows 10 1809 systems such as industrial control, healthcare, government, and critical infrastructure. A Secure Boot bypass could enable attackers to deploy persistent, low-level malware that evades detection by traditional antivirus and endpoint detection systems. This can lead to data breaches, system integrity compromise, and potential disruption of services. Organizations with strict compliance requirements (e.g., GDPR, NIS Directive) may face regulatory and reputational damage if exploited. The requirement for local high-privilege access somewhat limits remote exploitation but insider threats or lateral movement within networks could leverage this vulnerability to escalate privileges and establish persistence. Given the medium CVSS score, the threat is moderate but should not be underestimated due to the foundational nature of Secure Boot in system security. The absence of known exploits suggests a window of opportunity for defenders to remediate before active exploitation occurs.

1. Upgrade affected systems to a supported and fully patched version of Windows 10 or later (preferably Windows 11), as Windows 10 Version 1809 is legacy and may no longer receive security updates. 2. Implement strict access controls and monitoring to limit local administrative privileges and detect unusual privilege escalations or boot process modifications. 3. Employ hardware-based security features such as TPM (Trusted Platform Module) and ensure Secure Boot is enabled and properly configured in UEFI firmware settings. 4. Use endpoint detection and response (EDR) solutions capable of detecting boot-level tampering or rootkit behaviors. 5. Conduct regular audits of system firmware and boot configurations to detect unauthorized changes. 6. Develop and test incident response plans that include scenarios involving Secure Boot bypass and firmware-level compromise. 7. Educate IT staff and users about the risks of running outdated operating systems and the importance of timely patching and upgrades. 8. Monitor vendor advisories for patches or workarounds related to this CVE and apply them promptly once available.