CVE-2017-15114 in libvirtd
Summary
by MITRE
When libvirtd is configured by OSP director (tripleo-heat-templates) to use the TLS transport it defaults to the same certificate authority as all non-libvirtd services. As no additional authentication is configured this allows these services to connect to libvirtd (which is equivalent to root access). If a vulnerability exists in another service it could, combined with this flaw, be exploited to escalate privileges to gain control over compute nodes.
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Analysis
by VulDB Data Team • 01/25/2021
The vulnerability described in CVE-2017-15114 represents a critical security flaw in the OpenStack Platform director configuration for libvirtd service communication. This issue specifically affects deployments using tripleo-heat-templates where the libvirtd daemon is configured to utilize TLS transport for remote management. The fundamental problem lies in the default configuration approach that shares the same certificate authority across all non-libvirtd services within the OpenStack environment. This architectural decision creates an unintended attack vector where any service that can authenticate against the shared certificate authority can establish connections to libvirtd without additional authentication mechanisms.
The technical flaw stems from the absence of proper service-to-service authentication controls within the libvirtd configuration. When libvirtd operates in TLS mode with shared certificate authority, it effectively removes the need for additional authentication layers that should normally be required to establish connections to the hypervisor management interface. This configuration creates a scenario where any service within the shared certificate authority domain can connect to libvirtd, which by design operates with root privileges and full control over virtual machine management functions. The vulnerability essentially creates a privilege escalation pathway where an attacker controlling one service within the shared CA domain can leverage this access to gain root-level control over the compute node's virtualization layer.
The operational impact of this vulnerability extends far beyond a simple network access issue, representing a severe compromise of compute node security. The flaw enables attackers to achieve root-level access to compute nodes through the libvirtd service, which controls all virtual machine operations including creation, modification, and destruction of virtual environments. This access level allows for complete compromise of the underlying infrastructure, enabling attackers to manipulate virtual machines, steal data, establish persistence mechanisms, and potentially move laterally within the network. The vulnerability is particularly dangerous in cloud environments where compute nodes host multiple tenant virtual machines, as it allows for complete control over the hypervisor layer and all hosted workloads.
The security implications of this vulnerability align with CWE-284, which addresses improper access control in software systems, and represents a classic case of insufficient privilege separation. From an attack perspective, this flaw maps to multiple ATT&CK techniques including privilege escalation through service account access and lateral movement within the compute infrastructure. The vulnerability creates a dangerous scenario where a single compromised service within the shared certificate authority domain can be leveraged to gain complete root access to compute nodes. Organizations should implement immediate mitigations including configuring distinct certificate authorities for libvirtd and other services, implementing additional authentication mechanisms, and ensuring proper service isolation. The fix requires careful configuration management to separate the certificate authority used for libvirtd communication from that used by other services while maintaining proper operational functionality.