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Verify Hypervisor-Assisted Guest Mitigation (Spectre) patches using PowerCLI

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VMware recently published a new knowledge base (KB) article 52085 that outlines instructions for enabling the Hypervisor-Assisted Guest Mitigation (CVE-2017-5715), also known as the Spectre vulnerability. This KB also provides steps to verify the updated microcode (included in the ESXi patch) has been applied along with Virtual Machine verification (those applicable) to ensure that they are seeing the new CPU features. While following the KB and patching one of my vSphere environments, I had noticed the verification steps was not only manual but it also to difficult to scale beyond a few VMs as it required customers to look for a specific set of strings from within the vmware.log file which is generated for each powered on VM, which could easily be several hundreds or thousands of VMs.

I figured there had to be a better way to help customers automate this at scale and remove the human factor. The other reason I was not fond of the current method is that it would require customers to either enable ESXi Shell/SSH access or to manually or through automation to download every single vmware.log file to inspect for specific log entries which can take quite a bit of time for any sizable environment. I had an idea on how this could be done without having to look at the vmware.log file while leveraging our vSphere APIs and did some investigation. Before proceeding further, please familiarize yourself with KB 52085. For complete background on both Spectre (CVE-2017-5753 & CVE-2017-5715) and Meltdown (CVE-2017-5754) as it relates to all VMware products, please carefully read through this top level KB 52245 which is being updated as new information is available, so you may want to subscribe to the KB for all the latest updates.

UPDATE 4 (01/23/18) - VMware has just updated KB 52345 with the current list of Intel CPUs affected by Intel Sightings. I have also updated my script to reflect all these changes. Make sure to download the latest version to ensure you have the latest changes.

UPDATE 3 (01/16/18) - I have just enhanced the script further to also collect the current microcode version running on a given ESXi host. Unfortunately, this information can only be collected when SSH is enabled and is something a user must explicitly allow. The benefit here is that Intel Sighting impact reporting is more robust as the code now checks for both impacted CPU signature as well as the microcode affected by Intel Sighting as outline in KB 52345. See below for more details.

UPDATE 2 (01/14/18) - As mentioned in the last update, I have been working on a Intel Sighting remediation script which can help customers automate the temporary workaround as recommended in KB 52345. Please see this blog post for complete details.

UPDATE 1 (01/13/18) - VMware just published a new KB 52345 outlining certain Intel Broadwell and Haswell CPUs being affected by Intel Sightings after applying latest microcode updates. Please refer to the KB for the complete details. I am currently working on a script to help with the remediation as the remediation method outlined in the KB would require customers to enable SSH access and manually update /etc/vmware/config. In the meantime, I wanted to provide a way for customers to easily identify whether their system are affected by Intel Sightings and thanks to community member Adam Robinson who just submitted a patch this morning to update my existing script to include these details. I have also added the CPU model to the output as additional information.

Note: This script only provides information about your existing vSphere environment, it does not make any changes or provides any remediation steps, please follow the KB for those instructions.

The PowerCLI script is called VerifyESXiMicrocodePatch.ps1 and it contains the following two functions:

  • Verify-ESXiMicrocodePatchAndVM
  • Verify-ESXiMicrocodePatch

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Identifying ESXi boot method & boot device

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There was an interesting discussion on our internal Socialcast platform last week on figuring out how an ESXi host is booted up whether it is from local device like a disk or USB device, Auto Deploy or even boot from SAN along with its respective boot device? Although I had answered the question, I was not confident that we actually had a reliable and programmatic method for identifying all the different ESXi boot methods, which of course piqued my interest.

With a bit of trial and error in the lab, I believe I have found a method in which we can identify the ESXi boot type (Local, Stateless, Stateless Caching, Stateful or Boot from SAN) along with some additional details pertaining to the boot device. To demonstrate this, I have created the following PowerCLI script ESXiBootDevice.ps1 which contains a function called Get-ESXiBootDevice.

The function can be called without any parameters, in which it will query all ESXi hosts for a given vCenter Server and/or standalone ESXi host. You can also specify a specific ESXi host by simply passing in the -VMHostname option.

Here is an example output for one of my lab environments which shows several ESXi hosts and their different boot methods from local disk to Auto Deploy which can include stateless, stateless caching and stateful deployments. Depending on the BootType, the boot device shown in the Device column will either be the MAC Address of the NIC used to network boot the ESXi host or the identifier of a disk device. I have also included some additional details such as vendor/model along with the media type (SAS, SSD or USB) which is available as part of ESXCLI.


This script also supports ESXi environments that boot from SAN (FC, FCoE or iSCSI) and you can easily identify that with the word "remote" for the BootType. I would like to give a huge thanks to David Stamen who helped me out with the boot from SAN testing.

Cross vCenter Clone with vSphere 6.0+

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Similar to the Cross vCenter vMotion (xVC-vMotion) feature that was introduced in vSphere 6.0, Virtual Machine cloning can also be performed across two different vCenter Servers, regardless of their deployment type or SSO configurations. If vCenter Servers are part of an Enhanced Linked Mode (ELM), then a xVC-Clone operation can be initiated using the vSphere Web Client. However, if the vCenter Servers are not part of the same SSO Domain, then you will need to use the vSphere API to perform the operation similar to an xVC-vMotion.

Right before the holiday break, I had a few inquiries on providing some sample code that could demonstrate the Cross vCenter Clone (xVC-Clone) operation using the vSphere API. With that, I have created a new PowerCLI script called xNew-VM.ps1 which does exactly that and should feel familiar for anyone who has used my xMove-VM.ps1 script before. Before getting started, be sure to familiarize yourself with the requirements and supported configurations for xVC-Clone operations, which can be found here and here.

The script contains a number of variables that will need to be defined based on your specific environment. The following variables below pertain to the "source" vCenter Server from where you wish to initiate the clone operation from:

$sourcevmname = "PhotonOS-02"
$sourceVC = "vcenter65-1.primp-industries.com"
$sourceVCUsername = "*protected email*"
$sourceVCPassword = "VMware1!"

The following variables below pertain to the "destination" vCenter Server from where the cloned VM will be deployed to:

$destvmname= "PhotonOS-02-Clone"
$destVC = "vcenter65-3.primp-industries.com"
$destVCUsername = "*protected email*"
$destVCpassword = "VMware1!"
$datastorename = "vsanDatastore"
$datacenter = "Datacenter-SiteB"
$cluster = "Santa-Barbara"
$resourcepool = "MyRP" # cluster property not needed if you are using RP, useful for VMware Cloud on AWS
$vmhostname = "vesxi65-4.primp-industries.com"
$vmnetworkname = "VM Network"
$foldername = "Discovered virtual machine"
$switchtype = "vss"
$poweron = $false #optional
$snapshotname = "pristine" #optional

The last two variables are optional which merely controls whether the cloned VM is powered on and whether the source VM is being cloned while running, in which case, a snapshot is required.

Below is a screenshot of my two vCenter Servers, where vcenter65-1 is my "Source" and vcenter65-3 is my "Destination. I have a VM called PhotonOS-02 which is powered on and I have already taken a snapshot which I have named "pristine". I will then perform a xVC-Clone of the VM to the "Destination" vCenter Server and the new VM will be called "PhotonOS-02-Clone".


Once you have updated the script, you can simply execute it as shown in the screenshot below.


If we now head back over to our vSphere Web/H5 Client, we should now see the xVC-Clone operation start and shortly after (depending on the size of the VM being cloned), it should eventually appear on the destination vCenter Server that was specified in the script.


For quick and small deployments of a few VMs, the xVC-Clone feature can be quite handy. However, if you plan to deploy more than a couple of VMs, it would be more efficient to setup a vSphere Content Library which can configured to automatically sync all or specific content to the destination vCenter Server(s), which will help speed up deployment. I should also point out that cloning from vSphere 6.5+ from onPrem to VMware Cloud on AWS (VMC) also works and is fully supported in both direction which the vMotion/Provisioning PM had just shared with me. For VMC usage, you will need to ensure you specify the Compute-ResourcePool as the permission model in VMC is restrictive and you can not deploy directly to the vSphere Cluster and/or ESXi host.

Lastly, as mentioned earlier, the script I have provided is merely an example demonstrating the use of the xVC-Clone operation using the vSphere API and consuming it through PowerCLI. Unlike the Move-VM cmdlet which supports xVC operation natively, the New-VM does not currently support xVC-Clone. If you would like to see this natively supported as part of PowerCLI's New-VM cmdlet, be sure to add a +1 to PowerCLI Feature Request here.