CVE-2012-6314 in XenDesktop
Summary
by MITRE
Citrix XenDesktop Virtual Desktop Agent (VDA) 5.6.x before 5.6.200, when making changes to the server-side policy that control USB redirection, does not propagate changes to the VDA, which allows authenticated users to retain access to the USB device.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability identified as CVE-2012-6314 affects Citrix XenDesktop Virtual Desktop Agent versions 5.6.x prior to 5.6.200, representing a critical access control flaw that undermines the security posture of virtual desktop environments. This issue specifically targets the server-side policy management mechanism responsible for controlling USB redirection capabilities within virtual desktop infrastructure. The vulnerability stems from a failure in the policy propagation mechanism that governs how USB device access permissions are communicated from the central management server to individual virtual desktop agents. When administrators modify USB redirection policies on the server side, these changes are not effectively transmitted to the VDA components, creating a persistent security gap that allows unauthorized continued access to USB devices.
The technical flaw manifests as a policy synchronization failure within the Citrix XenDesktop architecture, where the server-side configuration updates do not properly cascade to the client-side VDA components. This creates a scenario where authenticated users can maintain access to USB devices even after administrators have explicitly revoked such permissions through policy modifications. The vulnerability operates at the intersection of access control and configuration management, where the expected behavior of centralized policy enforcement fails due to incomplete propagation mechanisms. This issue is particularly concerning within enterprise environments where USB device access represents a potential attack surface for data exfiltration, malware deployment, and privilege escalation attempts. The flaw essentially creates a persistent backdoor that bypasses the intended security controls designed to manage device access permissions.
The operational impact of CVE-2012-6314 extends beyond simple access control violations to potentially enable significant security breaches within virtualized desktop environments. Attackers who gain authenticated access to virtual desktops can leverage this vulnerability to maintain persistent access to USB devices even after administrators have attempted to revoke such permissions, effectively neutralizing security controls designed to protect against unauthorized physical device access. This vulnerability directly impacts the principle of least privilege and can enable attackers to exfiltrate sensitive data through USB storage devices, deploy malicious payloads, or establish persistent access points within the network. The persistence of this vulnerability means that even after administrators implement proper USB access policies, the compromised virtual desktops continue to allow unauthorized USB device access, undermining the integrity of the entire virtual desktop security framework.
Organizations affected by this vulnerability should immediately implement the patched version 5.6.200 or later releases from Citrix to address the policy propagation failure. Additionally, security teams should conduct comprehensive audits of USB access policies within their virtual desktop environments to identify any potential unauthorized access that may have occurred. Network segmentation and monitoring of USB device activity should be enhanced to detect anomalous behavior that might indicate exploitation of this vulnerability. The remediation process should include verification that policy changes are properly propagated across all VDA components and implementation of additional monitoring controls to detect unauthorized USB device connections. This vulnerability aligns with CWE-691, which addresses insufficient control flow management, and represents a significant concern within the ATT&CK framework under the technique of privilege escalation through persistence mechanisms, as it enables attackers to maintain access to physical device interfaces within virtualized environments.