Two weeks ago, I delivered a webinar about new security models in the cloud with Anne Thomas Manes from Burton Group. Anne had one slide in particular, borrowed from her colleague Dan Blum, which I liked so much I actually re-structured my own material around it. Let me share it with you:
This graphic does the finest job I have seen of clearly articulating where the boundaries of control lie under the different models of cloud computing. Cloud, after all, is really about surrendering control: we delegate management of infrastructure, applications, and data to realize the benefits of commoditization. But successful transfer of control implies trust–and trust isn’t something we bestow easily onto external providers. We will only build this trust if we change our approach to managing cloud security.
Cloud’s biggest problem isn’t security; it’s the continuous noise around security that distracts us from the real issues and the possible solutions. It’s not hard to create a jumbled list of things to worry about in the cloud. It is considerably harder to come up with a cohesive model that highlights a fundamental truth and offers a new perspective from which to consider solutions. This is the value of Dan’s stack.
The issues in the cloud that scare us the most all fall predicatably out of the change in control this environment demands. Enterprise IT has carefully constructed an edifice of trust based on its existing on-premise security models. Cloud challenges these models. Cloud rips pieces from the foundation of this trust, leaving a structure that feels unstable and untrustworthy.
We cannot simply maintain existing security models in the cloud; instead, we need to embrace a new approach to security that understands the give-and-take of control that is inherent to the cloud. This demands we recognize where we are willing to surrender control, acknowledge that this conflicts with our traditional model, and change our approach to assert control elsewhere. Over time we will gain confidence in the new boundaries, in our new scope of control, and in our providers–and out of this will emerge a new formal model of trust.
Let’s consider Infrastructure-as-a-Service (IaaS) as a concrete example. Physical security is gone; low-level network control is gone; firewall control is highly abstracted. If your security model–and the trust that derives from this–is dependent on controlling these elements, then you had better stay home or build a private cloud. The public cloud providers recognize this and will attempt to overlay solutions that resemble traditional security infrastructure; however, it is important to recognize that behind this façade, the control boundaries remain and the same stack elements fall under their jurisdiction. Trust can’t be invested in ornament.
If you are open to building a new basis for trust, then the public cloud may be a real option. “Secure services, not networks” must become your guiding philosophy. Build your services with the resiliency you would normally reserve for a DMZ-resident application. Harden your OS images with a similar mindset. Secure all transmissions in or out of your services by re-asserting control at the application protocol level. This approach to secure loosely coupled services was proven in SOA, and it is feasible and pragmatic in an IaaS virtualized environment. It is, however, a model for trust that departs from traditional network-oriented security thinking, and this is where the real challenge resides.
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