CVE-2015-5286 in Image Registry
Summary
by MITRE
OpenStack Image Service (Glance) before 2014.2.4 (juno) and 2015.1.x before 2015.1.2 (kilo) allows remote authenticated users to bypass the storage quota and cause a denial of service (disk consumption) by deleting images that are being uploaded using a token that expires during the process. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-9623.
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Analysis
by VulDB Data Team • 06/20/2022
The vulnerability described in CVE-2015-5286 represents a critical flaw in OpenStack Image Service (Glance) that enables authenticated remote attackers to circumvent storage quota mechanisms and potentially cause denial of service conditions through strategic image deletion operations. This issue specifically affects versions prior to 2014.2.4 (juno release) and 2015.1.2 (kilo release), highlighting the persistence of flawed security implementations that can be exploited even after initial patches have been applied. The vulnerability stems from an incomplete remediation of CVE-2014-9623, demonstrating how security fixes can sometimes contain gaps that leave systems vulnerable to sophisticated attacks.
The technical flaw manifests when users with valid authentication tokens attempt to delete images that are in the process of being uploaded to the Glance service. During this upload process, the system maintains temporary storage allocations that are not properly accounted for in the quota enforcement mechanisms. When an attacker deletes an image that is still being uploaded, the system's token expiration handling creates a race condition where the quota checks fail to properly validate whether the storage resources should be reclaimed or remain allocated. This creates a scenario where attackers can effectively consume disk space without proper quota enforcement, as the system fails to properly track and deduct storage usage from the user's allocated quota during the deletion operation.
The operational impact of this vulnerability extends beyond simple storage consumption issues and can lead to significant service disruption within OpenStack environments. Attackers can systematically consume available disk space by repeatedly performing these operations, potentially causing cascading failures in the cloud infrastructure where storage becomes exhausted and legitimate users cannot upload new images or create new instances. The vulnerability particularly affects multi-tenant environments where storage quotas are critical for resource isolation and fair usage policies. This flaw also creates potential for abuse in scenarios where attackers might deliberately target specific tenants or the overall system to cause service degradation, making it a serious concern for cloud operators who rely on Glance for image management and distribution.
The security implications of CVE-2015-5286 align with CWE-284 (Improper Access Control) and CWE-307 (Improper Restriction of Excessive Authentication Attempts) categories, as the vulnerability exploits weaknesses in access control mechanisms and authentication token handling. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and resource exhaustion, specifically targeting the system's storage management capabilities. Organizations should implement immediate mitigations including upgrading to patched versions of Glance, implementing additional monitoring for unusual deletion patterns, and establishing more robust quota enforcement mechanisms that properly account for transient storage states during upload operations. The vulnerability also underscores the importance of comprehensive testing of security patches and the need for thorough validation of fixes to prevent similar incomplete remediations in future security updates.
This vulnerability serves as a critical reminder of the complex interactions between authentication, authorization, and resource management in cloud environments, where seemingly simple operations can expose fundamental flaws in system design. The fact that this issue emerged from an incomplete fix for CVE-2014-9623 demonstrates the importance of careful regression testing and the potential for security vulnerabilities to persist in complex distributed systems. Organizations must maintain vigilant monitoring of their cloud infrastructure components and ensure that security patches are properly validated in their specific deployment environments before widespread rollout.