Hypervisor Security: Don't Trust, Verify

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VIrtualization Security

For years I've watched the delicate balance between enterprise IT groups and their security teams. Every now and then, there's a sea change in one area that gives rise to, let's say, passionate discussions. After attending last month's RSA conference, I feel one of those moments coming on, this time around production server virtualization. Specifically, we're talking about hardening the hypervisor--arguably one of the most important components of your virtual architecture.

What? Didn't think your CISO cared about hypervisors? Well, if he attended RSA, he does now. And if you have production VMs, you better get ready to prove they're secure. Don't expect your security team to just trust you.

Combating vulnerabilities (and passing audits) is a matter of starting from the root and working up. One option that impressed me at RSA is Intel's TXT (Trusted Execution Technology)--Intel's response to the Trusted Platform Module (TPM) specification published by the Trusted Computing Group and accepted as an ISO standard in 2009.

The foundation of this new trusted computing infrastructure is what's known as the "hardware root of trust," which establishes a bottoms-up security posture based on assuring the integrity of the VM kernel and loaded modules as they reside on disk and in memory. To take advantage, first make sure your server hardware supports TPM. Once you've verified that your gear has the correct processor extensions and supporting chipsets, it's just a matter of adding a small circuit board that plugs into a TPM slot on the server motherboard. After you enable TXT in the server BIOS that runs your host, you go through a process of generating the hash state that VMware ESXi, Xen, and other hypervisors will use during the boot process to detect unauthorized changes or whether malware has infiltrated the host operating system.

Moving up the stack, software vendor HyTrust offers a virtual appliance that can access the TXT status through the vSphere vCenter API and make decisions on controlling guest movement based on the classification status of the host server. HyTrust also offers network-based policy management for your virtual infrastructure that provides administrative access control, hypervisor hardening, and audit-quality logging to protect you from malicious, or sometimes just careless, insiders. Now when your security auditor asks for proof of hypervisor protection, you can go down your checklist: hardware root of trust (check), trusted virtualization environment (check), and security information and event management tools (check).

You're only going to increase your use of virtualization, so think in terms of evolving security. Evaluate where you are today and educate yourself as new hypervisor hardening options become available to ensure that you always stay a step ahead of the CISO--and the people after your data.

Schalk Theron is VP of security and operations for cloud services and ECM company SpringCM. Prior to joining SpringCM, Theron was at Washington Mutual, leading operational support for more than 50,000 users and a national network of more than 3,000 sites and multiple enterprise-class data centers supporting the award-winning Wamu.com. Write to us at [email protected].