CVE-2016-0757 in Image Service
Summary
by MITRE
OpenStack Image Service (Glance) before 2015.1.3 (kilo) and 11.0.x before 11.0.2 (liberty), when show_multiple_locations is enabled, allow remote authenticated users to change image status and upload new image data by removing the last location of an image.
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Analysis
by VulDB Data Team • 07/24/2022
The vulnerability identified as CVE-2016-0757 affects OpenStack Image Service (Glance) versions prior to 2015.1.3 (kilo) and 11.0.x prior to 11.0.2 (liberty). This issue arises from a flawed access control mechanism within the image management system that becomes exploitable when the show_multiple_locations configuration parameter is enabled. The vulnerability represents a significant security weakness that allows authenticated attackers to manipulate image data in ways that could compromise the integrity and availability of cloud image repositories.
The technical flaw stems from improper validation of image location modifications within the Glance service architecture. When show_multiple_locations is enabled, the system maintains multiple storage locations for images to support redundancy and distribution. However, the vulnerability occurs during the process of removing the final location from an image record. Attackers can exploit this by authenticating to the system with legitimate credentials and then manipulating the image metadata to remove all location entries. This action creates a condition where the system incorrectly processes subsequent image uploads, allowing the attacker to modify existing image status information and inject new image data into the repository.
The operational impact of this vulnerability extends beyond simple data manipulation as it enables a form of privilege escalation within the Glance service. An authenticated user can effectively bypass normal image management controls and potentially replace existing images with malicious content. This capability could be leveraged to introduce backdoors, malware, or other malicious payloads into the cloud infrastructure. The vulnerability also affects the integrity of image provenance tracking, as attackers could alter image status information to hide their activities or create false audit trails. Additionally, the ability to upload new image data means that attackers could potentially gain access to compute resources that depend on these images for instance creation.
From a cybersecurity perspective, this vulnerability aligns with CWE-284 (Improper Access Control) and represents a privilege escalation issue that violates the principle of least privilege. The ATT&CK framework categorizes this as a privilege escalation technique where an attacker leverages legitimate system functionality to gain elevated access rights. The vulnerability demonstrates how configuration parameters can create unexpected attack vectors when not properly validated. Organizations using OpenStack deployments with Glance services should consider this as a critical security issue that could lead to data compromise and system infiltration. The impact is particularly severe in multi-tenant environments where image integrity is crucial for maintaining security boundaries between different users and applications.
Mitigation strategies include upgrading to the patched versions of OpenStack Glance where the vulnerability has been addressed through proper validation of location removal operations. Administrators should disable the show_multiple_locations parameter when it is not required, as this prevents the exploitation path entirely. Additional protective measures include implementing strict access controls, monitoring image management activities, and conducting regular security audits of cloud image repositories. Organizations should also consider network segmentation and least-privilege access models to limit the potential impact of such vulnerabilities. The fix implemented in the patched versions addresses the core issue by ensuring proper validation of image location modifications and preventing unauthorized status changes during the image management process.