8.4.18 Ensure Host Guest File System Server is disabled


The Host Guest File System Server should be disabled if it is not needed.


Certain automated operations such as automated tool upgrades use a component in the hypervisor called Host Guest File System (HGFS), and an attacker could potentially use this to transfer files inside the guest OS. These VMX parameters don't apply on vSphere because VMware virtual machines work on vSphere and hosted virtualization platforms such as Workstation and Fusion. The code paths for these features, such as the Host Guest File System Server, are not implemented in ESXi. Explicitly disabling these features reduces the potential for vulnerabilities because it reduces the number of ways in which a guest can affect the host. Note that these are referenced for organizations that insist any documented setting, regardless of whether it is implemented in code or not, must have a value.


This will cause the VMX process to not respond to commands from the tools process. Setting isolation.tools.hgfsServerSet.disable to TRUE disables the registration of the guest's HGFS server with the host. APIs that use HGFS to transfer files to and from the guest operating system, such as some VIX commands or the VMware Tools auto-upgrade utility, will not function.


To set this configuration utilize the vSphere interface as follows:

Select the VM then select Actions followed by Edit Settings.

Click on the VM Options tab then expand Advanced.


Click on ADD CONFIGURATION PARAMS then input isolation.tools.hgfsServerSet.disable with a value of TRUE.

Click OK, then OK again.

To disable the Host Guest File System Server, run the following PowerCLI command:

# Add the setting to all VMs
Get-VM | New-AdvancedSetting -Name 'isolation.tools.hgfsServerSet.disable' -value $true

See Also


Item Details


References: 800-53|CM-6, 800-53|CM-7, CSCv7|9.2

Plugin: VMware

Control ID: 806f0b9fdd9cd26851c922851c9210a380e3f00f05baa387fe6b58f00ce3b283