Mitigating Multi-Tenancy Risks in IaaS Cloud Through Constraints-Driven Virtual Resource Scheduling

Abstract

A major concern in the adoption of cloud infrastructure-asa-service (IaaS) arises from multi-tenancy, where multiple tenants share the underlying physical infrastructure operated by a cloud service provider. A tenant could be an enterprise in the context of a public cloud or a department within an enterprise in the context of a private cloud. Enabled by virtualization technology, the service provider is able to minimize cost by providing virtualized hardware resources such as virtual machines, virtual storage and virtual networks, as a service to multiple tenants where, for instance, a tenant's virtual machine may be hosted in the same physical server as that of many other tenants. It is well-known that separation of execution environment provided by the hypervisors that enable virtualization technology has many limitations. In addition to inadvertent misconfigurations, a number of attacks have been demonstrated that allow unauthorized information flow between virtual machines hosted by a hypervisor on a given physical server. In this paper, we present attribute-based constraints specification and enforcement as a mechanism to mitigate such multi-tenancy risks that arise in cloud IaaS. We represent relevant properties of virtual resources (e.g., virtual machines, virtual networks, etc.) as their attributes. Conflicting attribute values are specified by the tenant or by the cloud IaaS system as appropriate. The goal is to schedule virtual resources on physical resources in a conflict-free manner. The general problem is shown to be NP-complete. We explore practical conflict specifications that can be efficiently enforced. We have implemented a prototype for virtual machine scheduling in OpenStack, a widely-used open-source cloud IaaS software, and evaluated its performance overhead, resource requirements to satisfy conflicts, and resource utilization.

Infrastructure as a service: Exploring network access control challenges

“…Therefore, it is more likely that there is a need for a new type of access control policy between tenants in intra-cloud communication [9]. A tenant can be an enterprise in the context of a public cloud or a department within an enterprise in the context of a private cloud [10]. The flexibility feature of IaaS enables the user to configure their own virtual machines and computing infrastructure [11].…”

“…Fine-grained attributebased access controls mechanism [12] Obtain virial recources in a secure manner Propose attribute-based constraints specification and enforcement [10] Multi-tenancy risks that arise in cloud IaaS…”

“…The access control models based on the attribute are recommended by several researchers [10,12,70,73]. On the other hand, it was claimed by Khamadja [68] that even the attribute-based model is not sufficient for cloud computing.…”

Expression and Enforcement of Security Policy for Virtual Resource Allocation in IaaS Cloud

“…In [28], different virtual resource orchestration constraints are resumed and expressed by attribute-based paradigm. Regarding these constraints, a conflict-free strategy is developed to mitigate risks in IaaS Cloud [29]. Most of above works have been motivated from security requirements expressed by CSC.…”

Sift - An Efficient Method for Co-residency Detection on Amazon EC2

“…Although, defenses against such vulnerabilities and researches on VM allocation and scheduling policies to mitigate multi-tenancy risks (Bijon et al, 2015); (Han et al, 2014) are already being proposed in the academic literature (Godfrey and Zulkernine, 2014); (Godfrey and Zulkernine, 2013); (Raj et al, 2009), multi-tenancy risk still cannot be ignored.…”