Secure your virtual infrastructure by using the following guidelines.
1) The DISA STIGs for vSphere 5 have been released:
http://iase.disa.mil/stigs/os/virtualization/esx.html
2) The VMware vSphere Hardening Guide is here:
http://blogs.vmware.com/vsphere/2013/04/vsphere-5-1-hardening-guide-official-release.html