The PCI Data Security Standard (PCI DSS) is due for an update next year, and the upcoming version of the standard could define securing cardholder data in virtualization environments.

The PCI Virtualization Special Interest Group (SIG), made up of auditors, vendors, merchants, banks, and quality security-assessment firms, this week met to hash out a proposal for how to include virtualization technology in PCI. The group is working on proposed changes to the DSS, as well as guidelines for how to map virtualization to the existing PCI spec.

"Because DSS does not even mention virtualization, there have been a lot of questions about how it applies, whether it can be used for PCI, and what areas are not in-scope," says Kurt Roemer, a member of the PCI board of advisers, chief security strategist for Citrix, and a member of the PCI DSS board of advisers. "We're addressing these questions."

The group is putting the final touches on a white paper and mapping "tool" document that explains where virtualization applies within each requirement of the DSS. "We're not out to replace or change PCI," Roemer says. Instead, the group is providing "an information supplement and additional guidance" for making virtualization environments PCI-compliant.

Roemer says the group is gathering additional input for proposed changes to the DSS. It will deliver the information to the PCI Standards Council, which meets in January to begin the process of building version 1.3 of the standard, due in October 2010. At this point, all of the proposals are basically a supplement to PCI, and it's up to the council to decide whether the spec itself is updated to include virtualization.

This is the latest effort in expanding PCI to incorporate emerging technologies. The PCI Security Standards Council (PCI SSC) recently unveiled best practices for retailers to defend themselves against the growing number of credit- and debit-card skimming scams, and in July a council working group created a set of recommendations for wireless deployment for PCI.

Mark Weiner, managing partner of virtualization vendor Reliant Security and a lead author of the PCI virtualization white paper, says companies and auditors have had to make their "own assumptions" in the absence of official PCI guidelines for virtualization. "That illustrates the need for this work," he says.

The hot topics are virtualization of point-of-sale (POS) systems and electronic commerce, Weiner says. "This is becoming hotter as retailers try to use virtualization for the cost benefit," he says. Ecommerce has raised issues, such as segmentation and the role of the hypervisor with cardholder data.

Among some of the technical issues are segmentation of the network, encryption, and how the presence or absence of virtualization will affect PCI compliance, says Richard Rees, security solutions director for SunGard Availability Services and a contributor to the PCI virtualization working group. "Answering questions -- such as, are all virtual machines on the same hypervisor as cardholder data VMs in scope, does virtualization violate the 'one primary function per server' tenet, and do virtual switches and virtual security appliances truly segment virtual environments on the same hypervisor -- are all things we are looking to the PCI Council, technical working group, and virtualization SIG to help answer," Rees says. "At this point, that's open to the interpretation of each QSA. "

And physical security with cloud computing is another tricky area that's under discussion. PCI DSS has specific requirements and audits for physical security. "If you're outsourcing part of your environment with cloud computing and don't understand their physical security, or can't get access to local controls, you're still obligated to protect [the cardholder data]," Rees says.

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