CVE-2015-5695 in Designate
Summary
by MITRE
Designate 2015.1.0 through 1.0.0.0b1 as packaged in OpenStack Kilo does not enforce RecordSets per domain, and Records per RecordSet quotas when processing an internal zone file transfer, which might allow remote attackers to cause a denial of service (infinite loop) via a crafted resource record set.
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Analysis
by VulDB Data Team • 11/12/2019
The vulnerability described in CVE-2015-5695 affects OpenStack Designate versions 2015.1.0 through 1.0.0.0b1, specifically within the OpenStack Kilo release cycle. This issue represents a critical flaw in the DNS service management component that handles zone file transfers between internal systems. The vulnerability stems from inadequate enforcement of resource quotas during the processing of internal zone file transfers, creating a potential attack vector that could severely impact system availability and stability.
The technical flaw manifests in the improper handling of RecordSets and Records quotas during internal zone file transfer operations. When processing these transfers, the system fails to validate that the number of RecordSets per domain and Records per RecordSet adhere to configured limits. This design oversight allows malicious actors to craft specially formatted resource record sets that can trigger an infinite loop condition within the DNS service processing logic. The vulnerability specifically targets the internal zone file transfer mechanism where the system should enforce strict quota boundaries but instead permits excessive resource consumption through malformed inputs.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise the entire DNS infrastructure within OpenStack deployments. Remote attackers can exploit this weakness to consume excessive system resources, leading to service degradation or complete system unavailability. The infinite loop condition created by the crafted resource record sets can cause the Designate service to become unresponsive, affecting DNS resolution capabilities for all domains managed through that OpenStack deployment. This type of attack directly violates the principle of resource isolation and can cascade into broader system failures affecting other services dependent on DNS resolution.
From a cybersecurity perspective, this vulnerability aligns with CWE-770, which addresses the allocation of resources without proper limits or controls. The flaw represents a classic example of insufficient input validation and resource management in distributed systems. The ATT&CK framework categorizes this under privilege escalation and denial of service tactics, where the attacker leverages a design flaw to consume excessive resources. The vulnerability also demonstrates poor adherence to the principle of least privilege and resource quota enforcement that should be fundamental in cloud infrastructure management. Organizations implementing OpenStack Designate should immediately implement mitigations including patching to affected versions, implementing stricter input validation, and enhancing monitoring for unusual resource consumption patterns during zone file transfer operations.
The root cause of this vulnerability highlights the importance of proper resource management and input sanitization in cloud DNS services. The absence of proper quota enforcement mechanisms during internal operations creates a dangerous attack surface that can be exploited without requiring elevated privileges. This flaw underscores the critical need for comprehensive security testing of internal APIs and service interactions, particularly in distributed cloud environments where multiple components must maintain strict resource boundaries. Organizations should also consider implementing additional monitoring and alerting for abnormal processing patterns that could indicate exploitation attempts, as the infinite loop condition may not be immediately apparent during normal system operation.