CVE-2023-0664 in QEMU
Summary
by MITRE • 03/29/2023
A flaw was found in the QEMU Guest Agent service for Windows. A local unprivileged user may be able to manipulate the QEMU Guest Agent's Windows installer via repair custom actions to elevate their privileges on the system.
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Analysis
by VulDB Data Team • 07/12/2025
The vulnerability identified as CVE-2023-0664 represents a privilege escalation flaw within the QEMU Guest Agent service for Windows operating systems. This issue affects the Windows installer component of the QEMU Guest Agent which is commonly deployed in virtualized environments to facilitate communication between guest operating systems and hypervisor platforms. The vulnerability stems from insufficient validation of custom actions during the repair installation process, creating an opportunity for malicious manipulation by local unprivileged users. The QEMU Guest Agent serves as a critical component in virtual machine management, providing services such as time synchronization, filesystem integration, and system information reporting that are essential for proper virtualization functionality.
The technical implementation of this vulnerability resides in the Windows Installer framework's handling of repair custom actions within the QEMU Guest Agent installer package. When a repair operation is initiated, the installer executes custom actions that are designed to maintain system integrity and proper service configuration. However, the flaw allows a local attacker to inject malicious code or manipulate existing custom actions during this repair process, potentially gaining elevated privileges beyond their current user context. This manipulation exploits the trust model inherent in the installer's execution flow, where the system grants elevated permissions to components that are expected to perform legitimate repair operations. The vulnerability specifically affects the installer's ability to validate and execute custom actions, creating a path for privilege escalation through the manipulation of installation state and execution contexts.
The operational impact of this vulnerability extends significantly within virtualized environments where QEMU Guest Agent is deployed. Local unprivileged users who gain access to a compromised virtual machine can leverage this flaw to elevate their privileges to SYSTEM level access, effectively bypassing standard user restrictions and gaining complete control over the virtual machine's operating system. This escalation capability enables attackers to perform actions such as modifying system files, installing malicious software, accessing sensitive data, and potentially using the compromised virtual machine as a pivot point for attacking other systems within the network infrastructure. The vulnerability is particularly concerning in enterprise environments where virtualization platforms are extensively used for development, testing, and production workloads, as it can provide attackers with a persistent foothold that may remain undetected for extended periods.
Mitigation strategies for CVE-2023-0664 should focus on immediate patching of affected QEMU Guest Agent versions and implementation of additional security controls. Organizations should prioritize updating to patched versions of QEMU Guest Agent that address the installer validation issues and custom action handling flaws. System administrators should implement least privilege principles for user accounts within virtualized environments and monitor for unauthorized installation or repair activities. The vulnerability aligns with CWE-284, which describes improper access control, and represents a specific instance of privilege escalation through installer manipulation. From an ATT&CK framework perspective, this vulnerability maps to techniques such as privilege escalation through exploitation of software vulnerabilities and persistence mechanisms. Network segmentation and access controls should be strengthened around virtualization platforms, while security monitoring solutions should be configured to detect unusual installer activity patterns that might indicate exploitation attempts. Regular security assessments of virtualization environments are recommended to identify and remediate similar vulnerabilities that could provide attackers with similar privilege escalation pathways.