The draft version of the vSphere 5.0 Hardening Guide
 provides guidance on how to securely deploy VMware vSphere 5 in a production environment. The focus is on initial configuration of the virtualization infrastructure layer, which covers the following:

  • The virtualization hosts
  • Configuration of the virtual machine container (NOT hardening of the guest operating system (OS) or any applications running within)
  • Configuration of the virtual networking infrastructure, including the management and storage networks as well as the virtual switch (but NOT security of the virtual machine’s network)
  • VMware vCenter Server, its database and client components

Source: VMware Communities