CVE-2013-2007 in Xen
Summary
by MITRE
The qemu guest agent in Qemu 1.4.1 and earlier, as used by Xen, when started in daemon mode, uses weak permissions for certain files, which allows local users to read and write to these files.
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Analysis
by VulDB Data Team • 05/10/2021
The vulnerability identified as CVE-2013-2007 affects the qemu guest agent component within Qemu version 1.4.1 and earlier implementations, particularly when deployed in Xen virtualization environments. This weakness manifests in the daemon mode operation where the guest agent fails to establish proper file permissions for critical system files, creating a significant security exposure for local users within the virtualized environment. The issue represents a fundamental failure in privilege separation and access control mechanisms that are essential for maintaining the security boundaries between guest operating systems and host environments.
The technical flaw stems from improper file permission handling within the qemu guest agent daemon, which operates with insufficiently restrictive access controls for files it creates or manages during runtime. This weakness allows local attackers who have access to the guest operating system to manipulate these files, potentially leading to unauthorized data access, modification, or even privilege escalation within the virtualized environment. The vulnerability specifically impacts the daemon mode execution context where the agent runs with elevated privileges to communicate with the hypervisor, yet fails to properly secure the communication channels and file system objects it manages.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it can enable attackers to gain unauthorized access to sensitive virtualization metadata, guest system information, or even manipulate the guest agent's behavior to facilitate further attacks. In Xen environments, where qemu guest agents are commonly used for system management and monitoring, this weakness can compromise the integrity of the virtualization layer and potentially allow attackers to escape the guest environment to target the host system or other virtual machines. The vulnerability affects the fundamental security model of virtualized environments where guest agents are trusted but improperly isolated from malicious local users.
Mitigation strategies for CVE-2013-2007 should focus on immediate remediation through version updates to Qemu 1.5.0 or later, which contain the necessary permission fixes for the guest agent files. System administrators should also implement additional monitoring of file system changes in guest agent directories and enforce proper access controls using discretionary access control mechanisms. The vulnerability aligns with CWE-732, which addresses inadequate protection of critical system resources, and represents a clear violation of the principle of least privilege as outlined in various cybersecurity frameworks. Organizations should also consider implementing mandatory access control policies and regular security audits of virtualization components to prevent similar issues in other system elements. This vulnerability demonstrates the critical importance of proper file permission management in daemon processes and highlights the need for comprehensive security testing of virtualization management components.