CVE-2013-0335 in Compute
Summary
by MITRE
OpenStack Compute (Nova) Grizzly, Folsom (2012.2), and Essex (2012.1) allows remote authenticated users to gain access to a VM in opportunistic circumstances by using the VNC token for a deleted VM that was bound to the same VNC port.
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Analysis
by VulDB Data Team • 01/01/2022
The vulnerability described in CVE-2013-0335 represents a critical security flaw in OpenStack Compute (Nova) versions Grizzly, Folsom, and Essex that emerged during 2012. This issue stems from improper handling of VNC tokens and port management within the virtual machine lifecycle, creating a window of opportunity for authenticated attackers to exploit temporal inconsistencies in resource allocation. The vulnerability specifically targets the VNC (Virtual Network Computing) access mechanism that allows remote administration of virtual machines through graphical interfaces. When a virtual machine is terminated or deleted, the system should properly release all associated resources including VNC ports and their corresponding tokens. However, in affected versions, the cleanup process was insufficient, leaving VNC tokens valid even after the associated virtual machine had been removed from the system. This creates a race condition where an authenticated user could potentially intercept and reuse VNC tokens from deleted virtual machines that were still bound to the same VNC port, thereby gaining unauthorized access to the graphical console of those terminated instances. The vulnerability operates under the premise that VNC tokens are generated based on specific parameters including port numbers and session identifiers, and when these are not properly invalidated upon VM deletion, attackers can exploit this temporal gap. This flaw directly relates to CWE-284, which addresses improper access control, and more specifically targets improper resource management within cloud computing environments. The attack vector requires the adversary to be authenticated within the OpenStack environment, making this a privilege escalation issue rather than a purely remote attack. From an operational perspective, this vulnerability significantly undermines the security isolation guarantees that virtual machines should maintain, as it allows unauthorized access to graphical console sessions of terminated instances. The implications extend beyond simple unauthorized access, potentially enabling attackers to execute malicious code, exfiltrate data, or perform other harmful activities within the compromised virtual machine's context. The vulnerability aligns with ATT&CK technique T1059, which involves command and scripting interpreter, as attackers could potentially use the compromised VNC access to execute commands within the target virtual machine. The impact is particularly severe in multi-tenant cloud environments where isolation between different users' virtual machines is paramount for security. Organizations running these vulnerable OpenStack versions face significant risk of data breaches, service disruption, and potential compliance violations, especially in regulated environments where virtual machine isolation is mandatory. The temporal nature of this vulnerability means that it may not be consistently reproducible, but the window of opportunity for exploitation exists whenever virtual machine deletion and port cleanup operations are not synchronized properly. This creates a challenging mitigation scenario where organizations must ensure immediate invalidation of VNC tokens upon VM deletion while maintaining proper resource management. The vulnerability also highlights broader issues in cloud infrastructure security where resource lifecycle management and access control mechanisms must be tightly synchronized to prevent such temporal security gaps. Remediation involves updating to patched versions of OpenStack Nova where proper resource cleanup and token invalidation mechanisms have been implemented. The vulnerability demonstrates the importance of comprehensive resource management in cloud computing environments and the critical need for proper access control enforcement throughout the entire virtual machine lifecycle, from creation to deletion. This issue serves as a reminder that cloud security requires attention to both the immediate security controls and the temporal consistency of resource management operations. The vulnerability's occurrence in widely used OpenStack versions underscores the importance of timely security updates and proper security testing of cloud infrastructure components before deployment in production environments. Organizations should implement monitoring for unusual VNC access patterns and establish robust procedures for validating access control mechanisms in their virtualized environments. This vulnerability also emphasizes the need for security considerations in cloud orchestration and resource management systems, where the proper coordination of multiple operations is essential for maintaining security boundaries between different virtualized environments and users. The attack scenario requires careful consideration of how authentication systems interact with resource management and access control, highlighting the complexity of securing modern cloud environments where multiple systems must coordinate properly to maintain security isolation.