PCI-DSS Virtualisation Guidance

In what was obviously a response to my recent blog post stating
more detailed guidance would be helpful (yes I am that influential!) the ‘PCI
Security Standards Council Virtualisation Special Interest Group’ have just
released the ‘PCI DSS Virtualisation Guidelines’ Information Supplement.

This can be found here;


This is a welcome addition to the PCI-DSS as it makes the
requirements for handling card data in a virtual environment much more clear.
The use of the recommendations in this document along with the reference
architecture linked to in my previous post will provide a solid basis for
designing PCI-DSS compliant virtual environment.

The document itself is in 3 main sections. These comprise;

– ‘Virtualisation Overview’ which outlines the various components
of a virtual environment such as hosts, hypervisor, guests etc. and under what
circumstances they become in scope of the PCI-DSS

– ‘Risks for Virtualised Environments’ outlines the key risks
associated with keeping data safe in a virtual environment including the
increased attack surface or having a hypervisor, multiple functions per system,
in memory data potentially being saved to disk, Guests of different trust
levels on the same host etc. along with procedural issues such as a potential
lack of separation of duties.

– ‘Recommendations’; This section is the meat of the document that
will be of main interest to most of the audience as it details the PCI’s recommended
actions and best practices to meet the DSS requirements. This is split into 4

– General –
Covering broad topics such as evaluating risk, understanding the standard,
restricting physical access, defence in depth, hardening etc.   There is also a recommendation to review other guidance such as that from NIST (National Institute of Standards Technology), SANS (SysAdmin Audit Network Security) etc. – this is generally
good advice for any situation where a solid understanding of how to secure a
system is required.

– Recommendations for Mixed Mode Environments –

This is a key section for most businesses as the reality for most of us is that being able to run a mixed mode environment, (where guests in scope of PCI-DSS and guests not hosting card data are able to reside on the same hosts and virtual environment via acceptable logical separation), are the best option in order to gain the maximum benefits from virtualisation.  This section is rather shorter than expected with little detail other than many warnings about how difficult true separation can be.  On a bright note it does clearly
say that as long as separation of PCI-DSS guests and none PCI-DSS guests can be configured and I would imagine audited then this mode of operating is permitted.  Thus by separating the Virtual networks and segregating the guests into separate resource pools, along with the use of virtual IPS appliances and likely some sort of auditing (e.g. a netflow monitoring tool) it should be very possible to meet the DSS requirements in a mixed mode virtual environment.

– Recommendations for Cloud Computing Environments –

This section outlines various cloud scenarios such as Public / Private / Hybrid along with the different service offerings such as IaaS (Infrastructure as a Service), PaaS (Platform as a Service), SaaS (Software as a Service).  Overall it is highlighted that in many cloud scenarios it may not be possible to meet PCI-DSS requirements due to the complexities around understanding where the data resides at all times and multi tenancy etc.

– Guidance for Assessing Risks in Virtual Environments –

This is a brief section outlining areas to consider when performing a risk assessment, these are fairly standard and include Defining the environment, Identifying threats and vulnerabilities.

Overall this is a useful step forward for the PCI-DSS as it clearly shows that the PCI are moving with the times and understanding that the use of virtual environments can indeed be secure providing it is well managed, correctly configured and audited.

If you want to make use of virtualisation for the benefits of consolidation, resilience and management etc. and your environment handles card data this along with the aforementioned reference architecture should be high on your reading list.



PCI-DSS compliance in a virtual environment

Version 2 of the PCI-DSS (Payment Card Industry – Digital Security Standard) that was released in October of last year (2010) finally added some much needed, if limited, clarification around the use of virtualised environments.

This change / clarification is an addition to section 2.2.1 of the standard, adding the statements;

Note: Where virtualization technologies are in use, implement only one primary function per virtual system component.


2.2.1.b If virtualization technologies are used, verify that only one primary function is implemented per virtual system component or device

While this does not clarify how to set up a virtual environment that handles card data to meet PCI-DSS it does at least make it very clear that the use of virtual environments is acceptable and can meet the standard.

This removes the previous confusion around the acceptability of of using virtualisation to host environments dealing with card data that stemmed from the statement in version one of the standard around each server having to have only a single function.  By definition the physical hosts in a virtualised environment host multiple guests (the virtual servers) and thus have multiple functions.

Despite not having as much detail as many had hoped this is a great step forward given the ever increasing adoption of virtualisation to reduce costs and make better use of server hardware.

This has also opened the door to the possibility of using cloud based services to provide a PCI-DSS compliant architecture.  During some recent research into virtual architecture that will meet the requirements of PCI-DSS 2 I came across this work from a combination of companies to provide a reference architecture for PCI-DSS compliance in a cloud based scenario;


The above links to both a webinar providing an overview of the work undertaken, and a white paper detailing the actual reference architecture.

The architecture design was undertaken by Cisco, VMWare, Savvis, Coalfire and Hytrust, and while the solution is understandably made up of the products and services offered by those companies, it clearly outlines a solution that you can adapt for your needs and make use of similar solutions that fit with your companies tech stack.  As such this is a highly recommended read for anyone involved in designing or auditing solutions that need to be PCI-DSS compliant.