CVE-2016-10746 in libvirt
Summary
by MITRE
libvirt-domain.c in libvirt before 1.3.1 supports virDomainGetTime API calls by guest agents with an RO connection, even though an RW connection was supposed to be required, a different vulnerability than CVE-2019-3886.
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Analysis
by VulDB Data Team • 09/04/2023
The vulnerability described in CVE-2016-10746 represents a significant authorization flaw within the libvirt virtualization management framework. This issue affects libvirt versions prior to 1.3.1 and specifically pertains to the handling of virDomainGetTime API calls through guest agents. The core problem lies in the improper enforcement of connection privileges, where read-only (RO) connections are incorrectly permitted to execute operations that should only be available to read-write (RW) connections. This misconfiguration creates a privilege escalation vector that undermines the security model of the virtualization infrastructure.
The technical implementation of this vulnerability stems from the libvirt daemon's insufficient validation of connection permissions when processing guest agent requests. When a guest agent attempts to retrieve domain time information through the virDomainGetTime API, the system fails to properly verify whether the initiating connection possesses the required RW privileges. This flaw allows malicious actors or compromised guest agents to perform time synchronization operations that should be restricted to authorized administrators with full control over the virtual domain. The vulnerability is particularly concerning because it operates at the hypervisor level, where guest agents typically have limited privileges but may be exploited to gain unauthorized access to sensitive system functions.
From an operational impact perspective, this vulnerability enables attackers to potentially manipulate or monitor time-related information within virtual machines without proper authorization. While the immediate functionality may appear limited to time retrieval, the underlying privilege escalation opens doors to more sophisticated attacks that could leverage this access for further exploitation. The vulnerability exists independently from CVE-2019-3886, indicating it represents a distinct security weakness in the libvirt authorization framework. This issue affects virtualized environments where guest agents are enabled, potentially compromising the integrity of time-sensitive operations and undermining the overall security posture of the virtual infrastructure.
The implications of this vulnerability extend beyond simple privilege escalation, as it demonstrates a fundamental flaw in libvirt's permission model that could be exploited in conjunction with other security weaknesses. Organizations using libvirt versions prior to 1.3.1 should consider this vulnerability as part of a broader security assessment of their virtualization environments. The flaw aligns with CWE-284, which addresses improper access control, and could potentially be leveraged in attacks following the privilege escalation techniques documented in the MITRE ATT&CK framework. System administrators should prioritize updating to libvirt 1.3.1 or later to address this authorization bypass, while also implementing additional monitoring for unauthorized guest agent activities that might indicate exploitation attempts. This vulnerability underscores the critical importance of proper privilege enforcement in virtualization management systems and highlights the need for comprehensive security testing of API access controls in hypervisor environments.