Recently, the cloud computing paradigm experienced an increase in popularity and expansion through small, medium
and large companies and enterprises as well as individuals.
This surge of interest has raised many concerns and fears related to many aspects of these systems such as security, performance, availability, ability of customization, difficulties
to integrate cloud with in-house IT, etc. A major concern
when using cloud computing is the security issue raised by
the fact that cloud computing systems allow users share resources even if are adversaries. This will allow cross Virtual
Machine (VM) attacks. A simple and very effective way of
preventing this kind of attacks is physically separating adversaries. In this pap er, we present a VM placement and
migration policy for Interclouds built around this idea.