Virginia Commerce Bank
Cloud computing is becoming more and more popular in computing infrastructure and it also introduces new security problems. For example, a physical server shared by many virtual machines can be taken over by an attacker if the virtual machine monitor is compromised through one of the virtual machines. Thus, collocating with vulnerable virtual machines, or "Bad neighbors", on the same physical server introduces additional security risks. Moreover, the connections between virtual machines, such as the network connection between a web server and its back end database server, are natural paths of attacks. Therefore, both virtual machine placement and connections among virtual machines in the cloud have great impact over the overall security of cloud.