CVE-2024-38067 is a vulnerability identified in the Windows Online Certificate Status Protocol (OCSP) server component of Microsoft Windows Server 2019, specifically version 10.0.17763.0. The flaw is categorized under CWE-400, which involves uncontrolled resource consumption. This means that the OCSP server does not properly limit or manage resource usage when processing certain requests, allowing an attacker to send specially crafted requests that consume excessive system resources such as CPU, memory, or network bandwidth. The consequence is a denial of service (DoS) condition, where legitimate OCSP responses become unavailable, potentially disrupting certificate validation processes critical for secure communications and authentication. The vulnerability can be exploited remotely over the network without requiring any authentication or user interaction, making it relatively easy to trigger. The CVSS v3.1 base score is 7.5, reflecting a high severity due to the network attack vector, lack of required privileges, and the impact limited to availability. No known public exploits or active exploitation campaigns have been reported as of the publication date. The vulnerability was reserved in June 2024 and published in July 2024, with no patch links currently available, indicating that mitigation may rely on forthcoming updates or workarounds.

For European organizations, the primary impact of CVE-2024-38067 is the disruption of OCSP services on Windows Server 2019 systems. OCSP is widely used to check the revocation status of digital certificates in real-time, which is critical for maintaining trust in secure communications, VPNs, email encryption, and other PKI-dependent services. A denial of service on the OCSP server can lead to failures in certificate validation, causing service interruptions, degraded security posture, or fallback to less secure methods. This can affect sectors such as finance, healthcare, government, and critical infrastructure that rely heavily on secure certificate validation. Additionally, prolonged outages could increase operational costs and damage organizational reputation. Since the vulnerability can be exploited remotely without authentication, attackers could target exposed OCSP servers to cause widespread disruption. The lack of known exploits currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once patches are released. Organizations with large-scale deployments of Windows Server 2019, particularly those hosting OCSP services internally or externally, face the highest risk.

1. Monitor Microsoft security advisories closely and apply patches immediately once they become available to address CVE-2024-38067. 2. Until patches are released, restrict network access to OCSP servers by implementing firewall rules or network segmentation to limit exposure to untrusted networks, especially the internet. 3. Employ rate limiting and traffic filtering on OCSP endpoints to detect and block abnormal request patterns indicative of resource exhaustion attempts. 4. Consider deploying redundant OCSP responders or failover mechanisms to maintain availability in case of an attack. 5. Review and harden server configurations to optimize resource allocation and prevent single points of failure. 6. Use monitoring and alerting tools to detect unusual resource consumption or service degradation on OCSP servers promptly. 7. Educate IT staff about the vulnerability and ensure incident response plans include scenarios involving OCSP service disruption. 8. Evaluate the use of alternative certificate validation methods temporarily if OCSP service availability cannot be guaranteed.