CVE-2007-5671 in Workstation
Summary
by MITRE
HGFS.sys in the VMware Tools package in VMware Workstation 5.x before 5.5.6 build 80404, VMware Player before 1.0.6 build 80404, VMware ACE before 1.0.5 build 79846, VMware Server before 1.0.5 build 80187, and VMware ESX 2.5.4 through 3.0.2 does not properly validate arguments in user-mode METHOD_NEITHER IOCTLs to the \\.\hgfs device, which allows guest OS users to modify arbitrary memory locations in guest kernel memory and gain privileges.
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Analysis
by VulDB Data Team • 01/25/2025
The vulnerability described in CVE-2007-5671 represents a critical privilege escalation flaw within VMware's HGFS (Host-Guest File System) driver implementation. This issue affects multiple VMware products including Workstation, Player, ACE, Server, and ESX platforms across several version ranges, demonstrating the widespread impact of improper input validation in kernel-mode drivers. The vulnerability resides in the HGFS.sys kernel driver component that facilitates communication between guest operating systems and the VMware hypervisor environment, specifically within the handling of METHOD_NEITHER IOCTL (Input/Output Control) operations.
The technical flaw manifests through inadequate argument validation within the kernel-mode driver when processing user-mode IOCTL requests directed to the \.\hgfs device interface. METHOD_NEITHER IOCTLs are a specific type of Windows driver communication pattern where the driver receives input parameters directly without automatic copying or validation by the operating system. This particular implementation fails to properly validate the parameters passed from user-mode applications, creating a path for malicious input to directly influence kernel memory operations. The vulnerability allows a guest operating system user to manipulate arbitrary memory locations within the kernel space, effectively bypassing normal memory protection mechanisms that should prevent user-mode processes from directly accessing or modifying kernel data structures.
The operational impact of this vulnerability is severe and directly enables privilege escalation from guest operating system user level to kernel-level execution privileges. Attackers exploiting this flaw can leverage the improperly validated IOCTL arguments to modify critical kernel memory locations, potentially allowing them to execute arbitrary code with the highest privileges available within the virtualized environment. This represents a fundamental breakdown in the security model of VMware virtualization platforms, as guest users can effectively break out of their isolated execution environment and gain control over the underlying hypervisor kernel. The implications extend beyond individual virtual machines since successful exploitation could enable attackers to compromise the entire virtualization infrastructure, affecting multiple VMs running on the same host system.
This vulnerability maps directly to CWE-125: "Out-of-bounds Read" and CWE-787: "Out-of-bounds Write" within the Common Weakness Enumeration framework, specifically demonstrating how improper input validation in kernel-mode drivers can lead to memory corruption vulnerabilities. From the MITRE ATT&CK framework perspective, this vulnerability enables T1055: "Process Injection" and T1068: "Local Privilege Escalation" techniques, allowing adversaries to execute code within the privileged context of the hypervisor kernel. The attack surface is particularly concerning given that the vulnerability affects multiple VMware product lines and version ranges, making it a prime target for exploitation across various virtualization environments. Organizations running affected VMware products should immediately implement mitigations including patching to the latest versions, disabling unnecessary virtualization features, and implementing network segmentation to limit potential attack vectors.
The root cause of this vulnerability stems from the lack of proper bounds checking and parameter validation within the kernel-mode driver code. When the HGFS.sys driver receives IOCTL requests, it should validate all input parameters against expected ranges and formats before processing them, particularly when dealing with memory addresses and buffer sizes that could potentially be manipulated by untrusted input. The failure to implement such validation creates a direct pathway for attackers to craft malicious IOCTL requests that manipulate kernel memory structures, effectively allowing arbitrary memory modification within the kernel address space. This type of vulnerability represents a classic example of how kernel-mode programming errors can lead to complete system compromise, as the kernel operates with the highest privileges and any memory corruption can result in arbitrary code execution or privilege escalation.