CVE-2013-7130 in Grizzly
Summary
by MITRE
The i_create_images_and_backing (aka create_images_and_backing) method in libvirt driver in OpenStack Compute (Nova) Grizzly, Havana, and Icehouse, when using KVM live block migration, does not properly create all expected files, which allows attackers to obtain snapshot root disk contents of other users via ephemeral storage.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability identified as CVE-2013-7130 represents a critical security flaw in the OpenStack Compute service known as Nova, specifically within the libvirt driver component that manages KVM virtual machines. This issue affects multiple versions of OpenStack including Grizzly, Havana, and Icehouse releases, making it a widespread concern across various cloud deployments. The vulnerability stems from improper file creation during the live block migration process, which is a feature that allows virtual machine storage to be migrated between hosts without downtime. When KVM live block migration is initiated, the system should create all necessary backing files and image files to maintain data integrity and isolation between virtual machines. However, the i_create_images_and_backing method fails to properly establish all expected files during this process, creating a significant security gap that can be exploited by malicious actors.
The technical implementation flaw occurs within the libvirt driver's handling of ephemeral storage management during live migration operations. During KVM live block migration, the system creates backing files that serve as the foundation for virtual disk images, establishing the relationship between the base image and the actual virtual machine storage. When the i_create_images_and_backing method does not properly create all expected files, it leaves gaps in the storage hierarchy that can be manipulated by unauthorized users. This improper file creation results in a situation where the storage isolation between virtual machines becomes compromised, allowing attackers to access snapshot root disk contents of other users. The vulnerability essentially creates a path where an attacker can traverse the storage hierarchy and potentially read data from other tenant's virtual machines, undermining the fundamental security principle of multi-tenancy in cloud environments. This issue is particularly dangerous because it operates at the storage layer, bypassing traditional network-based security controls and directly accessing the underlying storage infrastructure.
The operational impact of this vulnerability extends beyond simple data leakage, as it fundamentally compromises the security model of OpenStack deployments. Attackers exploiting this vulnerability can gain unauthorized access to sensitive data belonging to other tenants, potentially including personal information, business data, intellectual property, or system credentials. The attack vector is particularly concerning because it leverages legitimate system functionality - live block migration - to achieve unauthorized access. This means that the attack can occur during normal system operations without raising immediate alarms, making it difficult to detect and investigate. Organizations using OpenStack with KVM hypervisors and live migration capabilities are at risk, particularly those hosting multiple tenants or customers where data isolation is paramount. The vulnerability affects both the integrity and confidentiality aspects of the security triad, as it allows for unauthorized data reading and potentially could be extended to write operations depending on the specific implementation details.
Mitigation strategies for CVE-2013-7130 should focus on both immediate patching and operational security measures. Organizations should immediately upgrade to patched versions of OpenStack Nova that address this specific vulnerability in the libvirt driver, ensuring that all affected releases are updated to versions containing the necessary fixes. The remediation process should include thorough testing of the updated systems to ensure that live block migration functionality continues to operate correctly without introducing new issues. Additionally, implementing network segmentation and access controls around storage infrastructure can provide defense-in-depth measures to limit potential exploitation. Monitoring for unusual storage access patterns and implementing proper audit logging around live migration operations can help detect potential exploitation attempts. Organizations should also review their storage isolation practices and ensure that proper file system permissions and access controls are maintained throughout the storage hierarchy. This vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-264 (Permissions, Privileges, and Access Controls) categories, and represents a significant concern under ATT&CK framework domain of privilege escalation and credential access. The attack could be classified under T1078 (Valid Accounts) and T1565 (Data Manipulation) tactics, emphasizing the need for comprehensive security measures beyond simple patching to protect against potential exploitation.