CVE-2012-2693 in libvirt
Summary
by MITRE
libvirt, possibly before 0.9.12, does not properly assign USB devices to virtual machines when multiple devices have the same vendor and product ID, which might cause the wrong device to be associated with a guest and might allow local users to access unintended USB devices.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2012-2693 affects libvirt version 0.9.12 and earlier, presenting a critical security flaw in how USB device assignment operates within virtual machine environments. This issue stems from insufficient device identification mechanisms when multiple USB devices share identical vendor and product identifiers, creating a scenario where device mapping becomes ambiguous and potentially insecure.
The technical flaw manifests when libvirt attempts to assign USB devices to virtual machines without properly distinguishing between devices that share the same vendor and product ID combinations. This occurs because the system relies on incomplete device identification criteria, failing to utilize additional unique identifiers such as serial numbers or device-specific descriptors that would normally differentiate between otherwise identical devices. The vulnerability operates at the device assignment layer within libvirt's USB handling subsystem, specifically impacting the libvirt daemon's ability to correctly map USB devices to virtual machines.
From an operational perspective, this vulnerability creates a significant attack surface for local users who could potentially access unintended USB devices through misassigned device mappings. The impact extends beyond simple device access issues to encompass potential privilege escalation scenarios where attackers might exploit the incorrect device associations to gain unauthorized access to sensitive hardware resources. This flaw directly impacts the principle of least privilege in virtualization environments, as device assignment becomes unreliable and potentially exploitable.
The security implications of CVE-2012-2693 align with CWE-284 Access Control Issues, specifically addressing improper access control in device assignment mechanisms. The vulnerability also maps to ATT&CK technique T1059 Command and Scripting Interpreter, as local users could potentially leverage the misassigned USB devices to execute malicious code through compromised device access. Additionally, this issue relates to T1078 Valid Accounts, as attackers might use the device access to escalate privileges or gain additional system access through compromised USB device associations.
Mitigation strategies should focus on upgrading to libvirt version 0.9.12 or later, which contains the necessary fixes for proper USB device identification and assignment. System administrators should also implement additional monitoring of USB device assignments and consider implementing device-specific access controls that utilize multiple identification factors beyond vendor and product IDs. Organizations should conduct regular audits of their virtualization environments to ensure proper USB device mapping and implement least privilege principles for USB device access within virtual machines. The fix typically involves enhancing the device identification algorithm to incorporate additional unique identifiers and ensuring that device assignment logic properly handles cases where multiple devices share common identification attributes.