CVE-2024-35265 is a high-severity elevation of privilege vulnerability affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The vulnerability arises from a Time-of-check to Time-of-use (TOCTOU) race condition in the Windows Perception Service, a component responsible for handling sensor and perception-related data. A TOCTOU race condition occurs when a system checks a condition (such as permissions or resource state) and then uses the resource based on that check, but the state changes between the check and use, allowing an attacker to exploit the timing gap. In this case, the flaw allows an attacker with low privileges and local access to manipulate the timing window to escalate privileges to higher levels, potentially SYSTEM level. The CVSS v3.1 base score is 7.0, indicating high severity, with the vector AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. This means the attack requires local access (local vector), high attack complexity, low privileges, no user interaction, and impacts confidentiality, integrity, and availability at a high level. No known exploits are reported in the wild yet, and no patches are currently linked, suggesting it is a recently disclosed vulnerability. The vulnerability is specifically tied to Windows 10 Version 1809, which is an older version of Windows 10 but still in use in some environments. The CWE classification is CWE-367, which corresponds to TOCTOU race conditions, a common class of time-based race vulnerabilities that can lead to privilege escalation if exploited successfully.

For European organizations, this vulnerability poses a significant risk, especially for those still running Windows 10 Version 1809 in production environments. Successful exploitation can lead to local privilege escalation, allowing attackers who have gained limited access (e.g., through phishing or insider threats) to elevate their privileges to SYSTEM level. This can result in full system compromise, enabling installation of persistent malware, data exfiltration, or disruption of critical services. The high impact on confidentiality, integrity, and availability means sensitive data could be exposed or altered, and critical infrastructure could be disrupted. Sectors such as finance, healthcare, government, and critical infrastructure in Europe, which often have strict regulatory requirements for data protection and system integrity, are particularly at risk. Additionally, the lack of user interaction required for exploitation increases the threat level, as attackers can automate or script attacks once local access is obtained. The absence of known exploits in the wild currently provides a window for mitigation, but the presence of a high-severity vulnerability in a widely used OS version necessitates urgent attention.

European organizations should prioritize the following specific mitigation steps: 1) Identify and inventory all systems running Windows 10 Version 1809 to understand exposure. 2) Apply any available security updates or patches from Microsoft as soon as they are released; monitor Microsoft security advisories closely. 3) If patching is not immediately possible, consider upgrading affected systems to a more recent and supported Windows 10 version or Windows 11, which are less likely to be vulnerable. 4) Restrict local access to systems by enforcing strict access controls, limiting administrative privileges, and using endpoint protection solutions that can detect suspicious local activity. 5) Implement application whitelisting and behavior monitoring to detect attempts to exploit race conditions or escalate privileges. 6) Conduct regular security awareness training to reduce the risk of initial local access through social engineering or insider threats. 7) Use virtualization or sandboxing for high-risk applications to contain potential exploitation attempts. 8) Monitor system logs and security telemetry for unusual privilege escalation attempts or race condition exploitation indicators. These targeted steps go beyond generic advice by focusing on the specific nature of the vulnerability (local TOCTOU race condition) and the affected OS version.