Virtual machines (VMs) must limit console sharing.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-258708	VMCH-80-000195	SV-258708r933185_rule		Medium

Description
By default, more than one user at a time can connect to remote console sessions. When multiple sessions are activated, each terminal window receives a notification about the new session. If an administrator in the VM logs in using a VMware remote console during their session, a nonadministrator 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 VM. For example, if a jump box is being used for an open console session and the administrator loses connection to that box, the console session remains open. Allowing two console sessions permits debugging via a shared session. For the highest security, allow only one remote console session at a time.

Description

By default, more than one user at a time can connect to remote console sessions. When multiple sessions are activated, each terminal window receives a notification about the new session. If an administrator in the VM logs in using a VMware remote console during their session, a nonadministrator 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 VM. For example, if a jump box is being used for an open console session and the administrator loses connection to that box, the console session remains open. Allowing two console sessions permits debugging via a shared session. For the highest security, allow only one remote console session at a time.

STIG	Date
VMware vSphere 8.0 Virtual Machine Security Technical Implementation Guide	2023-10-11

Details

Check Text ( C-62448r933183_chk )
For each virtual machine do the following: From the vSphere Client, right-click the Virtual Machine and go to Edit Settings >> Advanced Parameters. 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-62448r933183_chk )

For each virtual machine do the following:

From the vSphere Client, right-click the Virtual Machine and go to Edit Settings >> Advanced Parameters.

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-62357r933184_fix)
For each virtual machine do the following: From the vSphere Client, right-click the Virtual Machine and go to Edit Settings >> Advanced Parameters. 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. 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 \| Set-AdvancedSetting -Value 1 Note: The VM must be powered off to configure the advanced settings through the vSphere Client. Therefore, it is recommended to configure these settings with PowerCLI as this 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.

Fix Text (F-62357r933184_fix)

For each virtual machine do the following:

From the vSphere Client, right-click the Virtual Machine and go to Edit Settings >> Advanced Parameters.

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.

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 | Set-AdvancedSetting -Value 1

Note: The VM must be powered off to configure the advanced settings through the vSphere Client. Therefore, it is recommended to configure these settings with PowerCLI as this 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.