147Technological Drivers for Cloud Computing
Both virtualization and multitenancy supports have to be implemented in
a secure manner. As virtualization and multitenancy become the norm in
cloud environments, it is critical that security be built-in at the core. When
servers are virtualized, it makes the creation of a new image possible with
little effort. This expansion of virtual images raises the risk of attack because
it increases the possibility that a security aw in the hypervisor can be
exploited by a guest instance. It can expose both existing systems and other
partners that interact with those systems to security threats. When security
is implemented as a framework within the OS, it improves the overall secu-
rity of both virtuali