The goal of CloudAudit is to provide a common interface and namespace that allows enterprises who are interested in streamlining their audit processes (cloud or otherwise) as well as cloud computing providers to automate the Audit, Assertion, Assessment, and Assurance of their infrastructure (IaaS), platform (PaaS), and application (SaaS) environments and allow authorized consumers of their services to do likewise via an open, extensible and secure interface and methodology.
Our execution mantra is straightforward:

• Keep it simple, lightweight and easy to implement; offer primitive definitions & language structure using HTTP(S)
• Allow for extension and elaboration by providers and choice of trusted assertion validation sources, checklist definitions, etc.
• Not require adoption of other platform-specific APIs
• Provide interfaces to Cloud naming and registry services

SaaS: this particular model is focused on managing access to applications. For example, policy controls may dictate that a sales person can only download particular information from sales CRM applications. For example, they are only permitted to download certain leads, within certain geographies or during local office working hours. In effect, the security officer needs to focus on establishing controls regarding users' access to applications.
PaaS: the primary focus of this model is on protecting data. This is especially important in the case of storage as a service. An important element to consider within PaaS is the ability to plan against the possibility of an outage from a Cloud provider. The security operation needs to consider providing for the ability to load balance across providers to ensure fail over of services in the event of an outage. Another key consideration should be the ability to encrypt the data whilst stored on a third-party platform and to be aware of the regulatory issues that may apply to data availability in different geographies.
IaaS: within this model the focus is on managing virtual machines. The CSOs priority is to overlay a governance framework to enable the organization to put controls in place regarding how virtual machines are created and spun down thus avoiding uncontrolled access and potential costly wastage.