CVE-2015-5694 in Designate
Summary
by MITRE
Designate does not enforce the DNS protocol limit concerning record set sizes
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Analysis
by VulDB Data Team • 02/26/2024
The vulnerability identified as CVE-2015-5694 affects the Designate DNS service component within OpenStack, specifically targeting the enforcement of DNS protocol standards regarding record set sizes. This issue represents a failure in protocol compliance where the system does not properly validate or restrict the maximum size of DNS record sets as defined by RFC 1035 and subsequent DNS specifications. The flaw exists in the validation logic that governs DNS resource record handling within the Designate service, which is responsible for managing DNS zones and records in OpenStack environments.
The technical implementation of this vulnerability stems from insufficient input validation mechanisms within the DNS record processing pipeline. When DNS record sets are submitted to the Designate service, the system fails to enforce the standard DNS protocol limit of 65535 bytes for record set sizes. This omission allows malicious actors to submit oversized DNS records that can potentially cause buffer overflows, memory exhaustion, or other resource-based denial of service conditions. The flaw operates at the application layer within the DNS protocol implementation, specifically affecting how the service handles record set validation and processing.
The operational impact of this vulnerability extends beyond simple protocol non-compliance to potentially enable various attack vectors including resource exhaustion attacks and denial of service conditions. An attacker could exploit this weakness by submitting DNS records exceeding the standard size limits, causing the Designate service to consume excessive memory resources or potentially trigger application crashes. This vulnerability particularly affects cloud environments where Designate is used for DNS management, as it could lead to service degradation or complete unavailability of DNS services for legitimate users. The impact is amplified in multi-tenant environments where a single malicious user could potentially affect other tenants through resource exhaustion attacks.
Mitigation strategies for CVE-2015-5694 should focus on implementing proper input validation and enforcement of DNS protocol standards within the Designate service. Organizations should ensure that all DNS record sets are validated against the standard 65535 byte limit before processing, with appropriate error handling for oversized records. This approach aligns with CWE-122, which addresses improper restriction of operations within a limited access scope, and follows ATT&CK technique T1499.004 for resource exhaustion. The implementation should include automated size checking mechanisms, logging of oversized record attempts, and proper error responses to prevent exploitation. System administrators should also consider implementing rate limiting and monitoring for unusual DNS record size patterns to detect potential abuse attempts. Regular security updates and patches to the OpenStack Designate service are essential to address this vulnerability at the source and maintain compliance with established DNS protocol standards.