CVE-2023-38200 is a vulnerability identified in the Keylime component of Red Hat Enterprise Linux 9. Keylime is a remote attestation framework designed to verify the integrity of systems using TPM (Trusted Platform Module) technology. The vulnerability stems from the blocking nature of the Keylime registrar's SSL connections, which can be exploited by an unauthenticated remote attacker to exhaust all available SSL connections. This uncontrolled resource consumption leads to a denial of service (DoS) condition, rendering the Keylime registrar unresponsive and potentially impacting the overall system's ability to perform integrity verification. The CVSS v3.1 base score is 7.5, reflecting a high severity due to the network attack vector, low attack complexity, no privileges required, and no user interaction needed. The vulnerability affects Red Hat Enterprise Linux 9 installations that utilize Keylime, although specific affected versions are not detailed. No known exploits have been reported in the wild as of the publication date. The flaw does not impact confidentiality or integrity but severely affects availability, which is critical for systems relying on Keylime for security assurance. The blocking behavior causing resource exhaustion suggests that the registrar does not properly handle concurrent SSL connections or lacks adequate connection management controls, making it susceptible to flooding attacks.

For European organizations, the primary impact of CVE-2023-38200 is the potential disruption of system integrity verification services provided by Keylime on Red Hat Enterprise Linux 9. This can lead to denial of service conditions that prevent the validation of system trustworthiness, which is especially critical in sectors such as finance, government, healthcare, and critical infrastructure. The inability to perform remote attestation could delay detection of compromised systems or prevent automated security responses, increasing overall risk exposure. Additionally, service outages caused by exhausted SSL connections may affect dependent applications and services, leading to operational downtime and potential regulatory compliance issues. Organizations with large-scale deployments of Red Hat Enterprise Linux 9, particularly those leveraging Keylime for security assurance, may experience significant operational impact. The lack of confidentiality or integrity compromise reduces the risk of data breaches but does not mitigate the severity of availability loss. Given the network-based attack vector and no requirement for authentication, attackers can launch DoS attacks from remote locations, increasing the threat surface for European entities.

1. Monitor Red Hat advisories closely and apply official patches or updates addressing CVE-2023-38200 as soon as they become available. 2. Restrict network access to the Keylime registrar service by implementing firewall rules that limit connections to trusted hosts and networks only. 3. Deploy network-level protections such as rate limiting, connection throttling, and intrusion prevention systems (IPS) to detect and block excessive SSL connection attempts targeting the Keylime registrar. 4. Consider isolating the Keylime registrar on dedicated network segments or virtual LANs to reduce exposure to untrusted networks. 5. Regularly audit and monitor SSL connection metrics and logs for unusual spikes or patterns indicative of resource exhaustion attempts. 6. Evaluate alternative or additional remote attestation solutions that provide better resilience against resource exhaustion attacks. 7. Implement robust incident response plans to quickly identify and mitigate denial of service conditions affecting Keylime services. 8. Engage with Red Hat support and security teams for guidance and early access to patches or workarounds.