Application of quantitative security metrics in cloud computing

Security issues are still prevalent in cloud computing particularly public cloud. Efforts by Cloud Service Providers to secure out-sourced resources are not sufficient to gain trust from customers. Service Level Agreements (SLAs) are currently used to guarantee security and privacy, however research into SLAs monitoring suggests levels of dissatisfaction from cloud users. Accordingly, enterprises favor private clouds such as OpenStack as they offer more control and security visibility. However, private clouds do not provide absolute security, they share some security challenges with public clouds and eliminate other challenges. Security metrics based approaches such as quantitative security assessments could be adopted to quantify security value of private and public clouds. Software quantitative security assessments provide extensive visibility into security postures and help assess whether or not security has improved or deteriorated. In this paper we focus on private cloud security using OpenStack as a case study, we conduct a quantitative assessment of OpenStack based on empirical data. Our analysis is multi-faceted, covering OpenStack major releases and services. We employ security metrics to determine the vulnerability density, vulnerability severity metrics and patching behavior. We show that OpenStack´s security has improved since inception, however concerted efforts are imperative for secure deployments, particularly in production environments.