CVE-2015-2687 in Compute
Summary
by MITRE
OpenStack Compute (nova) Icehouse, Juno and Havana when live migration fails allows local users to access VM volumes that they would normally not have permissions for.
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Analysis
by VulDB Data Team • 01/08/2021
The vulnerability identified as CVE-2015-2687 represents a critical access control flaw within OpenStack Compute (nova) versions Icehouse, Juno, and Havana that manifests during live migration operations. This issue arises from improper handling of volume permissions when virtual machine instances are migrated between compute hosts without proper cleanup of storage access controls. The flaw enables local users to maintain access to virtual machine volumes that should normally be restricted based on their permissions, creating a significant security risk in cloud environments where multiple tenants share the same infrastructure. The vulnerability specifically impacts the live migration functionality, which is a core feature allowing virtual machines to be moved between physical hosts without downtime while maintaining service availability.
The technical root cause of this vulnerability stems from inadequate cleanup of storage access controls during the live migration process. When a virtual machine undergoes live migration, the system should properly revoke access permissions to the underlying storage volumes for the previous host and grant appropriate access to the new host. However, in affected OpenStack versions, this cleanup mechanism fails, leaving volume access controls in an inconsistent state. Local users with access to the source compute host can potentially continue accessing the virtual machine volumes even after migration has completed, effectively bypassing normal access control mechanisms that should prevent unauthorized data access. This behavior violates fundamental principles of cloud security where tenant isolation must be maintained across all operations, including migration events.
The operational impact of CVE-2015-2687 extends beyond simple unauthorized access to create potential data breaches and privilege escalation scenarios within OpenStack environments. Attackers could leverage this vulnerability to access sensitive tenant data stored on volumes that should be restricted to specific users or administrative roles. The vulnerability particularly affects multi-tenant cloud deployments where different organizations share the same physical infrastructure but require strict data isolation. During live migration failures, the system's inability to properly manage volume access creates a window of opportunity for malicious actors to exploit the inconsistent access control state, potentially leading to data exfiltration, modification of sensitive information, or lateral movement within the cloud infrastructure. This vulnerability directly contravenes the cloud security principle of least privilege and can undermine the trust model that cloud providers rely on to maintain customer confidence.
Organizations affected by this vulnerability should implement immediate mitigations including applying the relevant security patches provided by OpenStack maintainers, configuring additional access control measures, and monitoring for unauthorized volume access patterns during migration operations. The fix typically involves ensuring proper cleanup of volume access controls during live migration processes and implementing more robust access control validation mechanisms. This vulnerability aligns with CWE-284 (Improper Access Control) and can be mapped to ATT&CK technique T1078 (Valid Accounts) and T1565 (Data Manipulation) as attackers may use the compromised access to maintain persistence or manipulate data. Additionally, the issue demonstrates characteristics of privilege escalation through improper resource handling during system operations, making it particularly dangerous in environments where automated migration processes are common. Organizations should also consider implementing network segmentation and additional monitoring controls to detect and prevent unauthorized access to storage volumes during migration events.