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

01.11.2018 by William Lam // 80 Comments

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

[Read more...]

Categories // Automation, ESXi, Security, vSphere Tags // cpuid.IBPB, cpuid.IBRS, cpuid.STIBP, Intel Sighting, microcode, plink, PowerCLI, Spectre, vsish

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William is Distinguished Platform Engineering Architect in the VMware Cloud Foundation (VCF) Division at Broadcom. His primary focus is helping customers and partners build, run and operate a modern Private Cloud using the VMware Cloud Foundation (VCF) platform.

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