ESXI5-VM-000037 - The system must disconnect unauthorized serial devices.

Information

Besides disabling unnecessary virtual devices from within the virtual machine, ensure no device is connected to a virtual machine if it is not required to be there. For example, serial and parallel ports are rarely used for virtual machines in a datacenter environment, and CD/DVD drives are usually connected only temporarily during software installation. For less commonly used devices that are not required, either the parameter should not be present or its value must be FALSE. NOTE: The parameters listed are not sufficient to ensure a device is usable; other parameters are required to indicate specifically how each device is instantiated. Any enabled or connected device represents another potential attack channel.

Solution

Configure the VM with the correct '<keyword> = <keyval>' pair.

To edit a powered-down virtual machine's .vmx file, first remove it from vCenter Server's inventory. Manual additions to the .vmx file from ESXi will be overwritten by any registered entries stored in the vCenter Server database. Make a backup copy of the .vmx file. If the edit breaks the virtual machine, it can be rolled back to the original version of the file.

Open the vSphere/VMware Infrastructure (VI) Client and log in with appropriate credentials.
If connecting to vCenter Server, click on the desired host.
Click the Configuration tab.
Click Storage.
Right-click on the appropriate datastore and click Browse Datastore.
Navigate to the folder named after the virtual machine, and locate the <virtual machine>.vmx file.
Right-click the .vmx file and click Remove from inventory.

Temporarily disable Lockdown Mode and enable the ESXi Shell via the vSphere Client.

Open the vSphere/VMware Infrastructure (VI) Client and log in with appropriate credentials.
If connecting to vCenter Server, click on the desired host.
Click the Configuration tab.
Click Software, Security Profile, Services, Properties, ESXi Shell, and Options, respectively.
Start the ESXi Shell service, where/as required.

As root, log in to the ESXi host and locate the VM's vmx file.
# find / | grep vmx

Add the following to the VM's vmx file.
keyword = 'keyval'

Where:
keyword = serialX.present (X >= 0)
keyval = FALSE

Re-enable Lockdown Mode on the host.

Re-register the VM with the vCenter Server:
Open the vSphere/VMware Infrastructure (VI) Client and log in with appropriate credentials.
If connecting to vCenter Server, click on the desired host.
Click the Configuration tab.
Click Storage.
Right-click on the appropriate datastore and click Browse Datastore.
Navigate to the folder named after the virtual machine, and locate the <virtual machine>.vmx file.
Right-click the .vmx file and click Add to inventory. The Add to Inventory wizard opens.
Continue to follow the wizard to add the virtual machine.

Item Details

Audit Name: DISA STIG VMWare ESXi 5 Virtual Machine STIG v2r1

Category: CONFIGURATION MANAGEMENT

Plugin: VMware

Control ID: 0ac5fd1ac1f033eef71909a201c6820fc8709b8952377cb20d86b70e5a53a9e4

Detections

Analytics

ESXI5-VM-000037 - The system must disconnect unauthorized serial devices.

Information

Solution

See Also

Item Details