CVE-2015-5251 in Image Service
Summary
by MITRE
OpenStack Image Service (Glance) before 2014.2.4 (juno) and 2015.1.x before 2015.1.2 (kilo) allow remote authenticated users to change the status of their images and bypass access restrictions via the HTTP x-image-meta-status header to images/*.
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Analysis
by VulDB Data Team • 06/25/2022
The vulnerability identified as CVE-2015-5251 affects OpenStack Image Service (Glance) versions prior to specific patch releases, creating a critical authorization bypass flaw that enables authenticated attackers to manipulate image metadata. This vulnerability resides within the HTTP header processing mechanism of the Glance service, specifically targeting the x-image-meta-status header parameter. The flaw allows malicious users to escalate their privileges by altering image status indicators, effectively circumventing the access control mechanisms that should govern image visibility and availability within the OpenStack environment.
The technical implementation of this vulnerability stems from inadequate input validation and insufficient authorization checks within the Glance service's metadata handling routines. When authenticated users submit requests containing the x-image-meta-status header, the system fails to properly validate whether the requesting user has authorization to modify the specific image status field. This represents a classic case of improper access control as defined by CWE-285, where the system does not adequately verify that the user possesses the necessary permissions to perform the requested metadata modification. The vulnerability operates at the application layer and can be exploited through standard HTTP requests, making it particularly dangerous as it requires minimal privileges to execute.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the integrity of the image management system within OpenStack deployments. Attackers can manipulate image visibility by changing status fields such as 'queued', 'saving', 'active', or 'killed', potentially making private images publicly accessible or hiding images from authorized users. This manipulation capability directly violates the principle of least privilege and can lead to data exposure, unauthorized access to sensitive images, and potential compromise of the entire OpenStack infrastructure. The vulnerability affects both the Juno release series prior to 2014.2.4 and the Kilo release series prior to 2015.1.2, indicating a widespread impact across multiple OpenStack versions and deployments.
Mitigation strategies for CVE-2015-5251 require immediate patching of affected OpenStack Glance services to the recommended versions that contain the necessary authorization checks and input validation improvements. Organizations should implement network segmentation and access controls to limit exposure of Glance endpoints to unauthorized users, while also monitoring for suspicious metadata modification patterns. The implementation of proper input validation mechanisms, including strict header validation and authorization verification before any metadata changes are accepted, should be enforced. Additionally, organizations should conduct comprehensive security audits of their OpenStack deployments to identify other potential authorization bypass vulnerabilities, as this flaw demonstrates weaknesses in the overall access control architecture that may affect other components of the cloud infrastructure. This vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation through manipulation of system processes.