Enterprises got some much needed clarification on the implementation of PCI requirements in virtualised environments on Tuesday.
The PCI Security Standards Council, the body that administers the Payment Card Industry Data Security Standard (PCI DSS),has released a comprehensive set of guidelines that companies can use to ensure that their virtual environments are compliant with PCI requirements.
The council's 39-page guidance document describes in detail how each of the 12 broad PCI security controls that are mandated for logical environments, need to be applied in a virtual setting. One section provides examples of how virtualisation can impact each PCI requirement, and recommends best practices for addressing them.
"The guidelines really address all aspects and usage of virtualisation," by organisations that are covered under PCI rules, said Kurt Romer, chief security strategist at Citrix Systems and chairman of the PCI special interest group that drafted the document.
"We put out the document to help people understand how they should be looking at [virtualisation]," from the PCI standpoint, Romer said.
One important area that the document covers relates to the hypervisor technologies that are used in hardware virtualisation. The guidance makes it clear that hypervisors fall under the scope of PCI requirements if any virtual component connected is covered under PCI, he said.
Similarly, the document also makes some important recommendations for mixed-mode environments, in which companies might choose to run PCI workloads alongside non-PCI data on the same virtual machine. The document for instance, spells out how in-scope and out of scope workloads need to be segmented and the additional measures needed to achieve that in a virtual environment, Romer said.
The PCI council's latest guidance also makes important recommendations with regard to PCI compliance in cloud environments. It spells out the extent to which enterprises are responsible for ensuring compliance and the extent to which cloud vendors are responding for ensuring the right controls are in place.
The document notes that companies which choose to have their PCI workloads hosted on multi-tenant, public cloud infrastructures need to ensure that their cloud vendors have additional controls for protecting their data.
Those challenges involved in protecting PCI data in a multi-tenant environment, "may make it impossible for some cloud-based services to operate in a PCI DSS compliant manner," the document noted. "Consequently, the burden for providing proof of PCI DSS compliance for a cloud-based service falls heavily on the cloud provider, and such proof should be accepted only based on rigorous evidence of adequate controls."
The guidance document should sort out some of the prevailing confusion surrounding the applicability of PCI in virtual settings, said Jim Huguelet, an independent PCI consultant.
"This is the best document that the PCI Security Standards Council has written to date in terms of really thinking about the breadth of the [issue] and then providing specific recommendations and best practices," Huguelet said.
The clarifications surrounding hypervisors and mixed-mode environments are particularly useful because of the uncertainty that has surrounded both topics for sometime, he said.
"Traditionally there's been a fair degree of ambiguity as to how PCI applied to virtual environments," added Richard Park, product manager at Sourcefire. "The guidelines make it more explicit how PCI is applicable to virtualisation."
As examples, Park pointed to sections in the guidance document that spell out how firewalls need to be used to provide segmentation between different workloads and how specialised intrusion detection and intrusion prevention tools might sometimes be needed to monitor traffic in virtual environments.
Also key are recommendations on how companies need to separate server administration and security administration tasks in virtual environments to ensure appropriate segregation of duties.
"Virtualisation was one of the biggest areas left untouched [by PCI rules]," said Avivah Litan, an analyst with Gartner. "It was unknown territory for a lot of people."
"This is one of the more helpful documents," Litan said. "This really fleshes things out."