  Cloud computing provides an effective business model for the deployment of IT
infrastructure, platform, and software services. Often, facilities are
outsourced to cloud providers and this offers the service consumer
virtualization technologies without the added cost burden of development.
However, virtualization introduces serious threats to service delivery such as
Denial of Service (DoS) attacks, Cross-VM Cache Side Channel attacks,
Hypervisor Escape and Hyper-jacking. One of the most sophisticated forms of
attack is the cross-VM cache side channel attack that exploits shared cache
memory between VMs. A cache side channel attack results in side channel data
leakage, such as cryptographic keys. Various techniques used by the attackers
to launch cache side channel attack are presented, as is a critical analysis of
countermeasures against cache side channel attacks.
