CVE-2016-5330 in Workstation
Summary
by MITRE
Untrusted search path vulnerability in the HGFS (aka Shared Folders) feature in VMware Tools 10.0.5 in VMware ESXi 5.0 through 6.0, VMware Workstation Pro 12.1.x before 12.1.1, VMware Workstation Player 12.1.x before 12.1.1, and VMware Fusion 8.1.x before 8.1.1 allows local users to gain privileges via a Trojan horse DLL in the current working directory.
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Analysis
by VulDB Data Team • 05/23/2025
The vulnerability described in CVE-2016-5330 represents a critical untrusted search path issue within VMware's HGFS (Host Guest File System) functionality that affects multiple VMware products including ESXi hypervisor versions 5.0 through 6.0 and various workstation and fusion applications. This flaw exists in the way VMware Tools handles dynamic link library loading during shared folder operations, creating a privilege escalation vector that can be exploited by local attackers. The vulnerability specifically impacts versions of VMware Tools that were released prior to the respective security patches, with affected product lines including VMware Workstation Pro and Player 12.1.x versions before 12.1.1, and VMware Fusion 8.1.x versions before 8.1.1, alongside VMware ESXi 5.0 through 6.0.
The technical mechanism behind this vulnerability stems from improper handling of the Windows DLL search order within the HGFS implementation. When VMware Tools processes shared folder operations, it loads DLLs from the current working directory without proper validation or sanitization of the search path. This behavior aligns with CWE-427, which describes uncontrolled search path dependencies where applications search for libraries in insecure locations. The flaw allows an attacker to place a malicious DLL with the same name as a legitimate VMware component in the current working directory, causing the system to load the attacker-controlled code instead of the legitimate library. This particular implementation follows the ATT&CK technique T1068 which involves local privilege escalation through the exploitation of system vulnerabilities.
The operational impact of this vulnerability is significant as it enables local users to achieve privilege escalation from standard user level to system level access, potentially allowing full control over the affected system. An attacker who gains access to a user account on a compromised VMware virtual machine can leverage this vulnerability to execute arbitrary code with elevated privileges, effectively bypassing the standard security boundaries between guest and host systems. The attack requires only local access to the system and does not need network connectivity or remote exploitation capabilities, making it particularly dangerous in environments where users might have access to virtual machines. The vulnerability affects both Windows and Linux guest operating systems, though exploitation methods may vary between platforms. The risk is amplified in enterprise environments where virtual machines are commonly used for development, testing, and production workloads, as successful exploitation could lead to complete compromise of the virtualized infrastructure.
Mitigation strategies for CVE-2016-5330 should focus on immediate patching of all affected VMware products to the latest security releases that address the untrusted search path vulnerability. Organizations should ensure that all VMware Workstation Pro and Player installations are updated to version 12.1.1 or later, VMware Fusion to version 8.1.1 or later, and VMware ESXi systems are updated to appropriate patch levels. Additionally, system administrators should implement monitoring for suspicious DLL loading activities and consider implementing application whitelisting policies to prevent execution of unauthorized DLLs. The vulnerability also highlights the importance of proper privilege separation in virtualized environments and the need for regular security assessments of virtual machine configurations. Organizations should conduct comprehensive vulnerability assessments to identify any systems running affected VMware products and ensure that all virtual machines are updated to the latest security patches to prevent exploitation of this privilege escalation vector.