CVE-2018-6974 in ESXi
Summary
by MITRE
VMware ESXi (6.7 before ESXi670-201810101-SG, 6.5 before ESXi650-201808401-BG, and 6.0 before ESXi600-201808401-BG), Workstation (14.x before 14.1.3) and Fusion (10.x before 10.1.3) contain an out-of-bounds read vulnerability in SVGA device. This issue may allow a guest to execute code on the host.
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Analysis
by VulDB Data Team • 05/25/2023
The vulnerability identified as CVE-2018-6974 represents a critical out-of-bounds read flaw within the SVGA (Simple Virtual Graphics Adapter) device implementation across multiple VMware virtualization products. This vulnerability affects VMware ESXi versions prior to specific patch releases including ESXi670-201810101-SG for version 6.7, ESXi650-201808401-BG for version 6.5, and ESXi600-201808401-BG for version 6.0, alongside VMware Workstation 14.x before 14.1.3 and Fusion 10.x before 10.1.3. The flaw resides in how the virtual graphics adapter processes certain graphical commands and data structures, creating an opportunity for malicious code execution within the host system.
The technical nature of this vulnerability stems from improper bounds checking within the SVGA device driver implementation. When a guest operating system sends graphical commands to the virtual graphics adapter, the system fails to properly validate the size and boundaries of incoming data structures. This allows an attacker to craft specially crafted graphics operations that cause the SVGA driver to read memory locations beyond the intended buffer boundaries. The out-of-bounds read can potentially expose sensitive memory contents or trigger memory corruption that leads to arbitrary code execution. According to CWE-129, this vulnerability maps directly to improper validation of array index values, while the ATT&CK framework categorizes this under privilege escalation techniques through guest-to-host code execution.
The operational impact of this vulnerability is severe as it enables a guest operating system to gain unauthorized access to the host system's execution environment. An attacker with access to a virtual machine could exploit this vulnerability to execute arbitrary code with the privileges of the host system, effectively breaking the isolation boundary that separates guest and host environments. This compromises the fundamental security principle of virtualization where guest operating systems should remain isolated from each other and from the host system. The vulnerability particularly affects environments where multiple tenants share the same hypervisor infrastructure, as a compromised guest could potentially attack other guests or the underlying host system. Organizations running unpatched VMware products face significant risk of lateral movement attacks and complete system compromise.
Mitigation strategies for CVE-2018-6974 require immediate patching of all affected VMware products to their latest versions containing the security fixes. VMware has released patches for ESXi 6.7, 6.5, and 6.0, as well as updated versions of Workstation and Fusion that address this specific out-of-bounds read vulnerability. System administrators should also implement network segmentation and access controls to limit the potential attack surface, particularly in multi-tenant environments where guest isolation is critical. Additional defensive measures include monitoring for suspicious graphical operations and implementing virtual machine integrity checks. The vulnerability highlights the importance of maintaining up-to-date virtualization infrastructure and demonstrates how flaws in hypervisor components can create pathways for complete system compromise. Organizations should also consider implementing runtime protection mechanisms and regular security assessments to identify and remediate similar vulnerabilities in their virtualized environments.