vSphere 6.0 Hardening Guide – Overview of coming changes

The vSphere Hardening Guide provides guidance on how to securely deploy VMware vSphere in a production environment. The vSphere Hardening Guide also serves as a foundation upon which regulatory compliance objectives are built. These organizations map compliance guidelines with vSphere Hardening Guide guidelines.

Hardening Guides are an industry recognized method of implementing stricter security to meet regulatory and local security standards above and beyond frameworks like Common Criteria.

Version 6.0 of the vSphere Hardening Guide is the next step in the evolution of the guide. A goal of the vSphere 6.0 Hardening Guide is to make the guide easier to implement and assess.

The intent of this article is to go over some of the major changes that come with the new 6.0 guide prior to its release. Consider this your “heads up”.

Separation of programmatically configured and testable “settings” from operational guidance.

Within previous guides are a mixture of

  • Operational guidance – How you use the product
  • Programmatic Guidance – Set this value to “True”

Operational guidelines present unique challenges.

  1. They can be addressed or mitigated in many ways
  2. They are generally left open to interpretation
  3. In order to implement them they may require cross-functional support across an enterprise
  4. They are usually not something that can be automatically tested and verified. Instead, they rely on an individual signing off that they are done correctly

Consider the example of “Run your vCenter and ESXi management interfaces on a separate management network” as something that meets each of these bullet points.

For the vSphere 6.0 Hardening Guide, the “operational” or “best practices” guidelines have been moved to vSphere Security documentation. This, in no way, lessens their importance! However, each one of these will generally be specific to your environment and as such require conversations with your security professionals and your auditors on implementation details and attestation.

What are left are the things that can be checked via API’s, CLI’s and other tools for attestable values. In some cases, the default values are sufficient and the check is an audit to ensure that the value is correct. In others, it’s a new or different value.

Risk Profiles

Guidelines are grouped in “Risk Profiles”. Risk Profiles indicate the relative increase in security provided by the guidelines. Risk Profiles are grouped as follows.

Risk Profile 1: guidelines that only be implemented in the highest security production environments, e.g. top-secret government or military, extremely sensitive data, etc.

Risk Profile 2: guidelines that should be implemented for more sensitive production environments, e.g. those handling more sensitive data, those subject to stricter compliance rules, etc.

Risk Profile 3: guidelines that should be implemented in all production environments

Risk Profiles in Operational Guidance

In order to create a bridge from the old guide to the new guide + documentation, a separate spreadsheet containing the Operational Guidance, a link to the new location in the vSphere documentation for each guideline and the Risk Profiles values of each of those guidelines will be published.

But why do I need a Hardening Guide? Isn’t it secure by default?

Some customers ask “Then why not ship vSphere at Risk Profile 3 by default?!”. That’s a great question. vSphere, without any changes from the Hardening Guide, already meets Common Criteria standards of security.

By default, security is built into the product. Consider the isolation of virtual machine memory and instructions or the disabling of risky parameters or strong password policies. See the ESXI Security Whitepaper or my session INF2336 from VMworld 2014 for a deeper dive on security. The Hardening Guide builds upon that.

Like many other products in the industry, vSphere “out of the box” is shipped optimized for Proof of Concept and pilot deployments. It is when vSphere is put into a production environment that Hardening Guidelines should be reviewed and applied as necessary.

What other changes have been made to the guide?

Top to Bottom Review

vSphere 6.0 is the first major release in a few years. As such, it was a good time to do a complete review of the Hardening Guide. Guidelines were updated, added or removed based on the incorporation of newer technologies and removal of older technologies. This was done with the great support of the vSphere R&D team and a number of product managers.

New Taxonomy

The Hardening Guide is consumed not only by individuals but also by other software such as scripts, VMware Configuration Manager, vRealize Air Compliance and a number of 3rd party solutions and organizations.

The primary driver for a new taxonomy was

  1. Ease of production
  2. Ease of use by solutions
  3. Ease of automation

Production of the Hardening Guide has changed from editing the Excel spreadsheet by hand to a database-driven solution that provides numerous advantages such as versioning, collaboration and other benefits.

From a programmatic standpoint I believe the new taxonomy will make the consumption of the Hardening Guide easier by solutions and automation tools.

The previous generation of the guides grouped guidelines by vSphere components. In the Excel spreadsheet this meant separate tabs such as “ESXi”, “vCenter”, “vNetwork”.


Moving forward this changes to a flat taxonomy. Rather than grouping into separate tabs the vSphere 6.0 Hardening Guide will be a single sheet.

Guidelines will now be referenced as “Component.Guideline” For example, what used to be




Unique Names

One of the problems this solves is giving each guideline a unique name. Within the vSphere Hardening Guide there were some guidelines are “the same” (e.g. “configure-NTP”). With this taxonomy, these values become unique. For example:


configure-ntp ESXi



As mentioned, the vSphere 6.0 Hardening Guide will now be delivered as a single sheet Excel workbook rather than separate sheets. (That method will also be available for 6.0 but deprecated in future releases) Other methods of delivery such as CSV, PDF and XML are being considered. Your feedback will help define them.

Wrap up

In closing, the biggest goal of the vSphere Hardening Guide is to move towards making security easier to implement and manage. This is a first step of a process. It sets the stage for more things to come. By separating out the Operational Guidance from the Programmatic Guidance and creating a new taxonomy I hope to enable more interesting things moving forward.

A beta of the vSphere 6.0 Hardening Guide will made available in the near future.

Your feedback is valuable to me. You can reach me on Twitter at @vspheresecurity or via email directly at mfoley at