Gartner research indicates that at the end of 2009, only 18 percent of enterprise data center workloads that could be virtualized had been virtualized; the number is expected to grow to more than 50 percent by the close of 2012. As more workloads are virtualized, as workloads of different trust levels are combined and as virtualized workloads become more mobile, the security issues associated with virtualization become more critical to address.
Gartner has identified the six most common virtualization security risks together with advice on how each issue might be addressed:
Risk: Information security isn't initially involved in the virtualization projects
Survey data from Gartner conferences in late 2009 indicates that about 40 percent of virtualization deployment projects were undertaken without involving the information security team in the initial architecture and planning stages. Typically, the operations teams will argue that nothing has really changed — they already have skills and processes to secure workloads, operating systems (OSs) and the hardware underneath. While true, this argument ignores the new layer of software in the form of a hypervisor and virtual machine monitor (VMM) that is introduced when workloads are virtualized.
Gartner said that security professionals need to realize that risk that isn't acknowledged and communicated cannot be managed. They should start by looking at extending their security processes, rather than buying more security, to address security in virtualized data centers.
Risk: A compromise of the virtualization layer could result in the compromise of all hosted workloads
The virtualization layer represents another important IT platform in the infrastructure, and like any software written by human beings, this layer will inevitably contain embedded and yet-to-be-discovered vulnerabilities that may be exploitable. Given the privileged level that the hypervisor/VMM holds in the stack, hackers have already begun targeting this layer to potentially compromise all the workloads hosted above it. From an IT security and management perspective, this layer must be patched, and configuration guidelines must be established.
Gartner recommends that organizations treat this layer as the most critical x86 platform in the enterprise data center and keep it as thin as possible, while hardening the configuration to unauthorized changes. Virtualization vendors should be required to support measurement of the hypervisor/VMM layer on boot-up to ensure it has not been compromised. Above all, organizations should not rely on host-based security controls to detect a compromise or protect anything running below it.
Risk: The lack of visibility and controls on internal virtual networks created for VM-to-VM communications blinds existing security policy enforcement mechanisms
For efficiency in communications between virtual machines (VMs), most virtualization platforms include the ability to create software-based virtual networks and switches inside of the physical host to enable VMs to communicate directly. This traffic will not be visible to network-based security protection devices, such as network-based intrusion prevention systems.
Gartner recommends that at a minimum, organizations require the same type of monitoring they place on physical networks, so that they don't lose visibility and control when workloads and networks are virtualized. To reduce the chance of misconfiguration and mismanagement, they should favor security vendors that span physical and virtual environments with a consistent policy management and enforcement framework.
Risk: Workloads of different trust levels are consolidated onto a single physical server without sufficient separation
As organizations move beyond the "low-hanging fruit" of workloads to be virtualized, more critical systems and sensitive workloads are being targeted for virtualization. This is not necessarily an issue, but it can become an issue when these workloads are combined with other workloads from different trust zones on the same physical server without adequate separation.
At a minimum, enterprises should require the same type of separation required in physical networks today for workloads of different trust levels within the enterprise data center. They should treat hosted virtual desktop workloads as untrusted, and strongly isolate them from the rest of the physical data center. Enterprises are advised to evaluate the need for point solutions that are able to associate security policy to virtual machines' identities and that prevent the mixing of workloads from different trust levels on the same server.
Risk: Adequate controls on administrative access to the Hypervisor/VMM layer and to administrative tools are lacking
Because of the critical support the hypervisor/VMM layer provides, administrative access to this layer must be tightly controlled, but this is complicated by the fact that most virtualization platforms provide multiple paths of administration for this layer.
Gartner recommends restricting access to the virtualization layer as with any sensitive OS and favoring virtualization platforms that support role-based access control of administrative responsibilities to further refine who can do what within the virtual environment. Where regulatory and/or compliance requirements dictate, organizations should evaluate the need for third-party tools to provide tight administrative control.
Risk: There is a potential loss of separation of duties for network and security controls
When physical servers are collapsed into a single machine, it increases the risk that both system administrators and users will inadvertently gain access to data that exceeds their normal privilege levels. Another area of concern is which group configures and supports the internal virtual switch.
Gartner recommends that the same team responsible for the configuration of network topology (including virtual LANs) in the physical environment should be responsible for this in virtual environments. They should favor virtualization platform architectures that support replaceable switch code, so that the same console and policies span physical and virtual configurations.
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