VMware has posted a humorous blog entry on mixed mode security.

It is my opinion that most people are not up to speed on Virtualization Security and Compliance Solutions. If you can prove that the systems in a mixed mode are not communicating, you should be golden. If your QSA does not agree, it might be time to get a new QSA. Jkjkjkjkj, not really but… Click the link below to see what we talked about at VMworld. I was misquoted in this article, Computer World and several others. (I NEVER said QSA’s were ten years behind J ) Seriously, I have some good friends that are QSA’s…

One of the comments in response goes straight to the issue of a QSA’s role.

…let’s clear a few things up. First, QSA’s don’t approve PCI compliance. They assess, make recommendations and document the report on compliance (ROC), but ultimately it is the bank and card brand that will determine if risk is acceptable. Second, there are numerous organizations who have been running mixed mode with PCI and successfully worked with their QSA. Prior to PCI DSS v2.0, that work was all done on a case by case basis and covered under compensating controls. 2.0 tries to put a standard in place for all to follow, but PCI 2.0 Standards do not forbid use of mixed-mode. The virtualization supplement is merely guidance, (not the standard), and the supplement itself even states in 1D: “There is no one-size-fits-all method or solution to configure virtualized environments to meet PCI DSS requirements. Specific controls and procedures will vary for each environment, according to how virtualization is used and implemented.”

The real point is that there are best practices and appropriate technology solutions available that make it absolutely possible to securely use virtualization in a PCI CDE.

I wrote a response to this comment but it hasn’t been approved on the site yet. Here it is for reference:

…I don’t want to speak for all QSAs but since I am one I will speak for myself on my role and the question of mixed mode.

1) Your comment suggests a QSA is *only* a messenger of an entity’s compliance. I understand where you are coming from, because a QSA does not always get the final call, but that does not mean the QSA is just a messenger. It’s like calling a lower court judge just a messenger because a higher court or supreme court can overrule them.

The 2011 July assessor update to QSAs from the Security Standards Council (SSC) makes it clear that a QSA is expected to be making the difficult decisions:

“It should always be remembered that the active QSA has the ultimate responsibility for their client’s assessment and the evidence provided in the Report on Compliance.”

In other words the QSA ultimately is the one to determine with the entity if the risk is acceptable FIRST. Only then does a report get forwarded for review by internal QA, to verify SECOND at the QSA company level that risk is acceptable, before it is forwarded for QA review by the SSC who reviews it. By the time it gets to the SSC and card brands there should be nothing left to decide. That is why as a QSA we regularly have to be re-tested and certified. We have to demonstrate that we can determine if risk is acceptable at the first pass.

This goes beyond PCI SSC. Auditors perform analysis to determine health. The role of an assessor does not emphasize the collect and store/forward phase. That is just the first step. It is like when a doctor collects your records and listens to your answers. They do this to make a determination. If they collect your records only, and do not make an ultimate determination on risk, then they are not a qualified assessor.

2) You mention “solutions available that make it absolutely possible to securely use virtualization”.

That looks like an oxymoron to me. What exactly is “absolutely possible”? Secure use of virtual technology is possible but to protect the cardholder data it takes a lot more than just technology.

One of the flaws I see most often is from managing change. Assessments of mixed mode generally are not about the possibility of virtual environments but rather the reality of how they are managed. From that perspective there is still a lot of opportunity for better technology and practices to develop and address the many risks of mixed mode.