CVE-2018-6972 in Workstation
Summary
by MITRE
VMware ESXi (6.7 before ESXi670-201806401-BG, 6.5 before ESXi650-201806401-BG, 6.0 before ESXi600-201806401-BG and 5.5 before ESXi550-201806401-BG), Workstation (14.x before 14.1.2), and Fusion (10.x before 10.1.2) contain a denial-of-service vulnerability due to NULL pointer dereference issue in RPC handler. Successful exploitation of this issue may allow attackers with normal user privileges to crash their VMs.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/25/2023
The vulnerability identified as CVE-2018-6972 represents a critical denial-of-service flaw affecting multiple VMware virtualization products including ESXi hypervisor versions 5.5 through 6.7, VMware Workstation 14.x, and VMware Fusion 10.x. This issue stems from a NULL pointer dereference condition within the Remote Procedure Call (RPC) handler component of these virtualization platforms, creating a scenario where malicious actors can exploit this weakness to disrupt virtual machine operations. The vulnerability specifically affects systems running versions prior to the respective patch releases ESXi670-201806401-BG, ESXi650-201806401-BG, ESXi600-201806401-BG, ESXi550-201806401-BG, 14.1.2 for Workstation, and 10.1.2 for Fusion. The flaw manifests when legitimate user accounts attempt to interact with the RPC service, triggering a system crash that terminates the targeted virtual machine execution environment.
The technical nature of this vulnerability places it squarely within the Common Weakness Enumeration category of CWE-476, which specifically addresses NULL pointer dereference conditions. This weakness occurs when an application attempts to access memory through a pointer that has not been properly initialized or has been set to NULL, leading to system instability and potential service disruption. In the context of VMware's virtualization infrastructure, the RPC handler serves as a communication interface between different components of the hypervisor, facilitating various management and operational functions. When an attacker sends specially crafted RPC requests that result in NULL pointer dereference, the system fails to properly handle the invalid memory access, ultimately causing the virtual machine process to terminate unexpectedly. This behavior aligns with the ATT&CK framework's T1499.004 technique for Network Denial of Service, as the exploitation directly targets system resources to prevent normal operation.
The operational impact of CVE-2018-6972 extends beyond simple service disruption, creating potential cascading effects within virtualized environments where multiple VMs may be running on the same host system. Attackers with normal user privileges can leverage this vulnerability to cause arbitrary VM crashes, potentially leading to data loss, service interruptions, and operational downtime for organizations relying on VMware virtualization platforms. The vulnerability's accessibility means that even unprivileged users within the virtual environment can trigger the denial-of-service condition, making it particularly concerning for multi-tenant hosting environments or shared infrastructure deployments. Organizations may experience increased administrative overhead as system administrators must respond to frequent VM crashes and restore services, while the potential for extended downtime could impact business continuity and disaster recovery operations. The vulnerability affects both production and development environments, creating risk across the entire virtual infrastructure lifecycle.
Mitigation strategies for CVE-2018-6972 primarily focus on applying the vendor-provided security patches and updates released by VMware. System administrators should prioritize upgrading to the patched versions of ESXi, Workstation, and Fusion as specified in the advisory, ensuring that all virtualization components are running the latest secure builds. Additionally, implementing network segmentation and access controls can help limit the potential impact of exploitation by restricting access to RPC services and virtual machine management interfaces. Regular monitoring of system logs for unusual RPC activity and VM crash patterns can serve as early detection mechanisms for potential exploitation attempts. Organizations should also consider implementing virtual machine resource limits and isolation policies to minimize the impact should an attacker successfully exploit this vulnerability. The remediation process should include comprehensive testing of patched environments to ensure that the security update does not introduce compatibility issues with existing virtual machine configurations or deployed applications.