**Abstract**

Multitenancy introduces significant error and security challenges in the cloud depending on the location of the functionality to be shared and the required degree of isolation between the tenants. Existing approaches for securing the deployment of cloud-hosted services to serve multiple users have paid little attention to evaluating the effect of the varying degrees of multitenancy isolation on the security and access privilege of tenants (or components). In addition, approaches for securing the isolation of tenants (or components) are usually implemented at lower layers of the cloud stack and often apply to the entire system and not to individual tenants (or components). This study presents CLAMP (Cloud-based architectural approach for securing services through Multitenancy deployment Patterns) to securing the deployment of cloud-hosted services in a way that guarantees the required degree of isolation between the tenants. We evaluated the framework by applying it to a motivating cloud deployment problem. The findings show among other things that the framework can be used to select suitable deployment patterns, evaluate the effect of varying degrees of isolation on the cloud-hosted service, analyse the deployment requirements of cloud-hosted services and optimise the deployment of the cloud-hosted service to guarantee multitenancy isolation.

**Keywords:** security, cloud-hosted services, deployment, multitenancy, tenant isolation
