A Decentralized Information Flow Model for SaaS Application Security

Software as a Service(SaaS) is a popular cloud service, but the SaaS providers have no security garantee for users. The SaaS providers may insert some malicious code in their applications with the primary goal of lifting user data. In order to address this problem, we introduce the security approach of Decentralized Information Flow Control (DIFC) and present a DIFC model that applies at the granularity of operating system processes for SaaS application security. The model allows untrusted software to compute with private data while trusted code controls the dissemination of that data. The trusted code is small which can be monitored easily. In addition, the model can be used in existing applications and allows safe interaction between conventional and DIFC-aware processes. Finally, we prove that the new model can enforce the security requirements of SaaS users.