Console connection sharing must be limited on the virtual machine.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-94623	VMCH-65-000033	SV-104453r1_rule		Medium

Description
By default, remote console sessions can be connected to by more than one user at a time. When multiple sessions are activated, each terminal window gets a notification about the new session. If an administrator in the VM logs in using a VMware remote console during their session, a non-administrator in the VM might connect to the console and observe the administrator's actions. Also, this could result in an administrator losing console access to a virtual machine. For example, if a jump box is being used for an open console session and the admin loses connection to that box, then the console session remains open. Allowing two console sessions permits debugging via a shared session. For highest security, only one remote console session at a time should be allowed.

Description

By default, remote console sessions can be connected to by more than one user at a time. When multiple sessions are activated, each terminal window gets a notification about the new session. If an administrator in the VM logs in using a VMware remote console during their session, a non-administrator in the VM might connect to the console and observe the administrator's actions. Also, this could result in an administrator losing console access to a virtual machine. For example, if a jump box is being used for an open console session and the admin loses connection to that box, then the console session remains open. Allowing two console sessions permits debugging via a shared session. For highest security, only one remote console session at a time should be allowed.

STIG	Date
VMware vSphere 6.5 Virtual Machine Security Technical Implementation Guide	2019-10-01

Details

Check Text ( C-93813r1_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 RemoteDisplay.maxConnections value is set to 1. 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 RemoteDisplay.maxConnections If the virtual machine advanced setting RemoteDisplay.maxConnections does not exist or is not set to 1, this is a finding.

Check Text ( C-93813r1_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 RemoteDisplay.maxConnections value is set to 1.

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 RemoteDisplay.maxConnections

If the virtual machine advanced setting RemoteDisplay.maxConnections does not exist or is not set to 1, this is a finding.

Fix Text (F-100741r1_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 RemoteDisplay.maxConnections value and set it to 1. 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 RemoteDisplay.maxConnections -Value 1 If the setting exists, run: Get-VM "VM Name" \| Get-AdvancedSetting -Name RemoteDisplay.maxConnections \| Set-AdvancedSetting -Value 1

Fix Text (F-100741r1_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 RemoteDisplay.maxConnections value and set it to 1. 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 RemoteDisplay.maxConnections -Value 1

If the setting exists, run:

Get-VM "VM Name" | Get-AdvancedSetting -Name RemoteDisplay.maxConnections | Set-AdvancedSetting -Value 1