A layered approach to simplified access control in virtualized systems

Abstract

In this work, we show how the abstraction layer created by a hypervisor, or virtual machine monitor, can be leveraged to reduce the complexity of mandatory access control policies throughout the system. Policies governing access control decisions in today's systems are complex and monolithic. Achieving strong security guarantees often means restricting usability across the entire system, which is a primary reason why mandatory access controls are rarely deployed. Our architecture uses a hypervisor and multiple virtual machines to decompose policies into multiple layers. This simplifies the policies and their enforcement, while minimizing the overall impact of security on the system. We show that the overhead of decomposing system policies into distinct policies for each layer can be negligible. Our initial implementation confirms that such layering leads to simpler security policies and enforcement mechanisms as well as a more robust layered trusted computing base. We hope that this work serves to start a dialog regarding the use of mandatory access controls within a hypervisor for both increasing security and improving manageability.