HGFS file transfers must be disabled on the virtual machine.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-239338	VMCH-67-000007	SV-239338r679563_rule		Medium

Description
Setting isolation.tools.hgfsServerSet.disable to true disables 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, will not function. An attacker could potentially use this to transfer files inside the guest OS.

STIG	Date
VMware vSphere 6.7 Virtual Machine Security Technical Implementation Guide	2021-04-16

Details

Check Text ( C-42571r679561_chk )
From the vSphere Web Client right-click the Virtual Machine and go to Edit Settings >> VM Options >> Advanced >> Configuration Parameters >> Edit Configuration. Verify the isolation.tools.hgfsServerSet.disable value is set to true. or From a PowerCLI command prompt while connected to the ESXi host or vCenter server, run the following command: Get-VM "VM Name" \| Get-AdvancedSetting -Name isolation.tools.hgfsServerSet.disable If the virtual machine advanced setting isolation.tools.hgfsServerSet.disable does not exist or is not set to true, this is a finding.

Check Text ( C-42571r679561_chk )

From the vSphere Web Client right-click the Virtual Machine and go to Edit Settings >> VM Options >> Advanced >> Configuration Parameters >> Edit Configuration. Verify the isolation.tools.hgfsServerSet.disable value is set to true.

or

From a PowerCLI command prompt while connected to the ESXi host or vCenter server, run the following command:

Get-VM "VM Name" | Get-AdvancedSetting -Name isolation.tools.hgfsServerSet.disable

If the virtual machine advanced setting isolation.tools.hgfsServerSet.disable does not exist or is not set to true, this is a finding.

Fix Text (F-42530r679562_fix)
From the vSphere Web Client right-click the Virtual Machine and go to Edit Settings >> VM Options >> Advanced >> Configuration Parameters >> Edit Configuration. Find the isolation.tools.hgfsServerSet.disable value and set it to true. If the setting does not exist, add the Name and Value setting at the bottom of screen. Note: The VM must be powered off to configure the advanced settings through the vSphere Web Client so it is recommended to configure these settings with PowerCLI as it can be done while the VM is powered on. Settings do not take effect via either method until the virtual machine is cold started, not rebooted. or From a PowerCLI command prompt while connected to the ESXi host or vCenter server, run the following command: If the setting does not exist, run: Get-VM "VM Name" \| New-AdvancedSetting -Name isolation.tools.hgfsServerSet.disable -Value true If the setting exists, run: Get-VM "VM Name" \| Get-AdvancedSetting -Name isolation.tools.hgfsServerSet.disable \| Set-AdvancedSetting -Value true

Fix Text (F-42530r679562_fix)

From the vSphere Web Client right-click the Virtual Machine and go to Edit Settings >> VM Options >> Advanced >> Configuration Parameters >> Edit Configuration. Find the isolation.tools.hgfsServerSet.disable value and set it to true. If the setting does not exist, add the Name and Value setting at the bottom of screen.

Note: The VM must be powered off to configure the advanced settings through the vSphere Web Client so it is recommended to configure these settings with PowerCLI as it can be done while the VM is powered on. Settings do not take effect via either method until the virtual machine is cold started, not rebooted.

or

From a PowerCLI command prompt while connected to the ESXi host or vCenter server, run the following command:

If the setting does not exist, run:

Get-VM "VM Name" | New-AdvancedSetting -Name isolation.tools.hgfsServerSet.disable -Value true

If the setting exists, run:

Get-VM "VM Name" | Get-AdvancedSetting -Name isolation.tools.hgfsServerSet.disable | Set-AdvancedSetting -Value true