CVE-2024-29062 is a high-severity vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0). It is classified as a Time-of-check Time-of-use (TOCTOU) race condition (CWE-367) affecting the Secure Boot security feature. Secure Boot is a critical security mechanism designed to ensure that only trusted software is loaded during the system startup process, preventing unauthorized or malicious code from executing before the operating system loads. The vulnerability arises when there is a timing window between the verification of a condition (time-of-check) and the actual use of the verified resource (time-of-use), allowing an attacker to exploit this race condition to bypass Secure Boot protections. This bypass could enable an attacker to load unsigned or malicious bootloaders or kernel drivers, compromising the system's integrity at a fundamental level. The CVSS v3.1 base score is 7.1, indicating a high severity level. The vector string (AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H) shows that the attack requires adjacent network access, high attack complexity, no privileges, and user interaction, but results in high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability was reserved in mid-March 2024 and published in early April 2024, indicating recent discovery and disclosure. Given the nature of the vulnerability, it targets a fundamental security feature, making exploitation potentially impactful for system trustworthiness and security posture.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and government entities that rely on Windows 10 Version 1809 in their infrastructure. Successful exploitation could allow attackers to bypass Secure Boot, leading to the execution of unauthorized code at boot time, persistent malware infections, and potential full system compromise. This undermines the trustworthiness of endpoint devices, potentially leading to data breaches, espionage, or sabotage. Critical sectors such as finance, healthcare, energy, and public administration could be particularly affected due to their reliance on secure boot processes to protect sensitive data and maintain system integrity. The requirement for adjacent network access and user interaction somewhat limits remote exploitation but does not eliminate risk, especially in environments where users might be tricked into interacting with malicious content or devices. The high impact on confidentiality, integrity, and availability means that exploitation could result in data theft, system downtime, and loss of operational control. Additionally, legacy systems still running Windows 10 Version 1809 might not receive timely updates, increasing exposure. The absence of known exploits in the wild currently provides a window for mitigation before widespread attacks occur.

1. Immediate assessment and inventory: Identify all systems running Windows 10 Version 1809 (build 10.0.17763.0) within the organization, prioritizing critical assets and endpoints in sensitive environments. 2. Patch management: Although no patches are currently linked, monitor Microsoft’s official channels closely for security updates addressing this vulnerability and apply them promptly upon release. 3. Upgrade strategy: Plan and execute an upgrade to a supported and more recent Windows version that includes security improvements and ongoing support, reducing exposure to this and similar vulnerabilities. 4. Network segmentation: Limit adjacent network access by segmenting networks and restricting communication between devices, reducing the attack surface for this vulnerability. 5. User awareness and training: Educate users about the risks of interacting with untrusted devices or content that could trigger exploitation, emphasizing caution with USB devices and network shares. 6. Endpoint protection: Deploy advanced endpoint detection and response (EDR) solutions capable of detecting anomalous bootloader or driver behavior indicative of Secure Boot bypass attempts. 7. Secure Boot configuration audit: Verify Secure Boot settings in firmware and ensure they are properly configured and enforced to reduce the risk of bypass. 8. Incident response readiness: Prepare incident response plans specifically addressing boot-level compromises, including forensic capabilities to detect and remediate persistent threats.