CVE-2013-4291 in libvirt
Summary
by MITRE
The virSecurityManagerSetProcessLabel function in libvirt 0.10.2.7, 1.0.5.5, and 1.1.1, when the domain has read an uid:gid label, does not properly set group memberships, which allows local users to gain privileges.
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Analysis
by VulDB Data Team • 01/08/2022
The vulnerability identified as CVE-2013-4291 resides within the libvirt virtualization management library, specifically in the virSecurityManagerSetProcessLabel function across versions 0.10.2.7, 1.0.5.5, and 1.1.1. This flaw represents a critical privilege escalation vulnerability that exploits improper group membership handling during process label setting operations. The issue manifests when virtual machine domains utilize read uid:gid labels, creating a scenario where local attackers can manipulate their group memberships to elevate privileges within the system. This vulnerability directly impacts the security model of libvirt's mandatory access control mechanisms, which are designed to enforce strict isolation between virtualized environments and the host system. The flaw stems from insufficient validation of group membership assignments during the security label setting process, allowing malicious users to bypass intended access controls.
The technical implementation of this vulnerability involves the improper handling of group identifiers when transitioning process security contexts within libvirt's security management framework. When a domain reads and applies uid:gid labels, the virSecurityManagerSetProcessLabel function fails to correctly establish the complete set of group memberships for the process. This incomplete group membership setup creates a privilege escalation vector where local users can manipulate their effective group IDs to gain access to resources that should be restricted. The vulnerability operates at the intersection of Linux security controls and virtualization management, exploiting the gap between the intended security policy enforcement and actual implementation. This misconfiguration allows attackers to potentially access files, network resources, or system interfaces that should be restricted based on the virtual machine's security context. The flaw aligns with CWE-254, which addresses security weaknesses related to improper privileges and access controls, specifically focusing on inadequate group membership management in security-critical contexts.
The operational impact of CVE-2013-4291 extends beyond simple privilege escalation to potentially compromise entire virtualization environments. Local users who can manipulate processes within a libvirt-managed virtual machine can leverage this vulnerability to gain elevated privileges on the host system, effectively breaking the isolation that virtualization platforms are designed to maintain. This breach of isolation represents a significant threat to multi-tenant virtualization deployments where multiple users share the same physical infrastructure. The vulnerability enables attackers to potentially access other virtual machines, host system resources, or sensitive data that should remain isolated. In enterprise environments using libvirt for container orchestration or virtual machine management, this flaw could allow attackers to escalate from a compromised guest VM to full host system control, undermining the fundamental security assumptions of virtualization technologies. The impact is particularly severe in cloud computing environments where libvirt serves as a core component of infrastructure management.
Mitigation strategies for CVE-2013-4291 require immediate patching of affected libvirt versions to address the group membership handling flaw in the virSecurityManagerSetProcessLabel function. Organizations should implement comprehensive monitoring for unauthorized privilege escalation attempts and ensure that all virtualization platforms are updated to versions that have resolved this vulnerability. System administrators should review and tighten access controls for libvirt management interfaces, implementing least privilege principles for user accounts that interact with virtualization management functions. Additionally, organizations should consider implementing additional security controls such as mandatory access control policies, process monitoring, and regular security audits to detect and prevent exploitation attempts. The vulnerability demonstrates the importance of proper privilege management in security-critical systems and aligns with ATT&CK technique T1068, which covers privilege escalation through local exploits. Security teams should also implement network segmentation and monitoring to detect suspicious activities that might indicate exploitation attempts, particularly around process creation and privilege elevation events within virtualized environments.