CVE-2024-0567 in GnuTLS
Summary
by MITRE • 01/16/2024
A vulnerability was found in GnuTLS, where a cockpit (which uses gnuTLS) rejects a certificate chain with distributed trust. This issue occurs when validating a certificate chain with cockpit-certificate-ensure. This flaw allows an unauthenticated, remote client or attacker to initiate a denial of service attack.
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Analysis
by VulDB Data Team • 06/11/2024
The vulnerability identified as CVE-2024-0567 resides within the GnuTLS cryptographic library implementation used by the Cockpit web-based system administration tool. This flaw represents a critical security weakness that fundamentally undermines the certificate validation process, specifically affecting how distributed trust models are handled during certificate chain validation. The issue manifests when cockpit-certificate-ensure attempts to validate certificate chains, creating a scenario where legitimate certificate validations fail due to improper handling of trust distribution mechanisms. This vulnerability operates at the intersection of cryptographic protocol implementation and system administration interfaces, making it particularly dangerous in environments where remote access and automated certificate management are critical components of infrastructure security.
The technical root cause of this vulnerability stems from an inadequate implementation of certificate chain validation logic within the GnuTLS library as consumed by Cockpit. When processing certificate chains that rely on distributed trust models, the system fails to properly validate the complete chain structure, leading to validation failures that can be exploited by remote attackers. This flaw essentially creates a condition where the certificate validation process becomes unreliable and can be manipulated to cause system instability. The vulnerability specifically affects the cockpit-certificate-ensure utility which is responsible for ensuring proper certificate configuration and validation within the Cockpit environment, making it a direct threat to the integrity of the system's authentication infrastructure.
From an operational perspective, this vulnerability creates a significant denial of service risk that can be exploited by unauthenticated remote attackers without requiring any privileged access or credentials. The impact extends beyond simple service disruption as it fundamentally compromises the trust model that Cockpit relies upon for secure remote administration. Attackers can leverage this weakness to cause certificate validation failures that may result in complete service unavailability, preventing legitimate administrators from accessing system management interfaces. The distributed trust model aspect of this vulnerability means that even if individual certificates appear valid, the chain validation process fails, creating cascading effects that can impact multiple system components relying on Cockpit for administration.
Security mitigations for CVE-2024-0567 should prioritize immediate patching of affected GnuTLS versions and Cockpit implementations to address the certificate validation logic flaw. Organizations should implement network-level monitoring to detect unusual certificate validation patterns that might indicate exploitation attempts, while also reviewing their certificate management policies to ensure proper trust model implementation. The vulnerability aligns with CWE-295 which addresses improper certificate validation and relates to ATT&CK technique T1566 which covers credential access through various means including certificate manipulation. System administrators should also consider implementing certificate pinning mechanisms and regular certificate health checks to reduce the attack surface, while ensuring that any certificate validation processes are thoroughly tested to prevent similar issues in other components of the infrastructure stack.