Remote attestation consists of generating evidence of a system’s integrity via measurements and reporting the evidence to a remote party for appraisal in a form that can be trusted. The parties that exchange information must agree on formats and protocols. We assert there is a large variety of patterns of interactions among appraisers and attesters of interest. Therefore, it is important to standardize on flexible mechanisms for remote attestation. We make our case by describing scenarios that require the exchange of evidence among multiple parties using a variety of message passing patterns. We show cases in which changes in the order of evidence collection result in important differences to what can be inferred by an appraiser. We argue that adding the ability to negotiate the appropriate kind of attestation allows for remote attestations that better adapt to a dynamically changing environment. Finally, we suggest a language-based solution to taming the complexity of specifying and negotiating attestation procedures.

This work examines the use of model checking techniques to verify system-level security properties of a collection of interacting virtual machines. Specifically, we examine how local access control policies implemented in individual virtual machines and a hypervisor can be shown to satisfy global access control constraints. The SAL model checker is used to model and verify a collection of stateful domains with protected resources and local MAC policies attempting to access needed resources from other domains. The model is described along with verification conditions. The need to control state-space explosion is motivated and techniques for writing theorems and limiting domains explored. Finally, analysis results are examined along with analysis complexity.

Cloud computing uses virtualization to lease small slices of large-scale datacenter facilities to individual paying customers. These multi-tenant environments, on which numerous large and popular web-based applications run today, are founded on the belief that the virtualization platform is sufficiently secure to prevent breaches of isolation between different users who are co-located on the same host. Hypervisors are believed to be trustworthy in this role because of their small size and narrow interfaces.

Within the US Department of Defense, developers have been designing and implementing a prototype multilevel secure local area network (MLS LAN). Researchers at MITRE have been cooperating in this development by doing the security modeling. The MLS LAN has special dynamic features, such as the ability to add new security levels during normal operations and to modify label translation schemata, which distinguish it from other secure LANs. These features enhance the functionality of the LAN without compromising its security. The principal features of the MLS LAN are highlighted. Some of the design, implementation, and modeling issues are discussed.>