CVE-2016-9592 in openshift
Summary
by MITRE
openshift before versions 3.3.1.11, 3.2.1.23, 3.4 is vulnerable to a flaw when a volume fails to detach, which causes the delete operation to fail with 'VolumeInUse' error. Since the delete operation is retried every 30 seconds for each volume, this could lead to a denial of service attack as the number of API requests being sent to the cloud-provider exceeds the API's rate-limit.
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Analysis
by VulDB Data Team • 02/28/2023
The vulnerability identified as CVE-2016-9592 affects OpenShift versions prior to 3.3.1.11, 3.2.1.23, and 3.4, representing a critical flaw in the platform's storage management system that can be exploited to cause denial of service conditions. This vulnerability specifically manifests when volumes fail to detach properly from compute resources, creating a cascading effect that prevents successful deletion operations. The issue stems from the platform's handling of volume lifecycle management, where failed detachment events trigger repeated deletion attempts that are not properly coordinated or throttled.
The technical implementation of this vulnerability involves the orchestration layer's failure to properly manage volume detachment states, leading to persistent volume in use errors that prevent cleanup operations from completing successfully. When a volume cannot be detached, the system enters a retry loop that executes deletion operations every 30 seconds for each affected volume. This retry mechanism, while designed to ensure eventual consistency, becomes problematic when multiple volumes experience detachment failures simultaneously. The repeated API calls generated by these retry operations create a significant load on the underlying cloud provider's API endpoints, as each volume deletion attempt triggers a separate API request that must be processed by the cloud infrastructure.
The operational impact of this vulnerability extends beyond simple resource cleanup failures to create substantial denial of service conditions that can severely impact cluster availability and performance. The rate of API requests generated by the retry mechanism can quickly exceed the cloud provider's API rate limits, resulting in API throttling that affects not only the volume deletion operations but potentially other critical cluster functions that rely on the same cloud provider endpoints. This creates a scenario where legitimate cluster operations become blocked or delayed due to the excessive API load generated by the flawed volume management system, effectively rendering the cluster unable to properly manage storage resources and potentially impacting application availability.
The vulnerability demonstrates characteristics consistent with CWE-704, which covers improper handling of resource cleanup operations in software systems. From an attack perspective, this flaw aligns with techniques described in the MITRE ATT&CK framework under the T1499 category for resource consumption attacks, where adversaries can exploit system weaknesses to consume computational resources and cause service disruption. The repeated API calls create a form of API abuse that can be leveraged to exhaust rate limits, making this vulnerability particularly dangerous in multi-tenant environments where multiple clusters might be sharing the same cloud provider resources. Organizations should implement proper volume management policies and ensure that OpenShift clusters are updated to versions that address this specific detachment and retry handling issue to prevent exploitation and maintain system stability.
The mitigation strategy for this vulnerability requires immediate patching of affected OpenShift installations to versions that contain the corrected volume detachment handling logic. System administrators should also implement monitoring solutions that can detect unusual API request patterns and volume deletion failures that may indicate this vulnerability is being exploited. Additionally, cloud provider rate limiting configurations should be reviewed and potentially adjusted to provide more resilient handling of legitimate cluster operations while still maintaining appropriate protection against abuse. The fix implemented in the patched versions addresses the root cause by ensuring proper state management during volume detachment operations and implementing more intelligent retry mechanisms that do not overwhelm cloud provider APIs with excessive requests.