טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentOrlovsky Arie
SubjectDecentralized Enforcement of Security Policies for
Distributed Computational Systems
DepartmentDepartment of Computer Science
Supervisor Professor Dan Raz
Full Thesis textFull thesis text - English Version


Abstract

The shift from single server environments to globally distributed systems presents a great challenge in terms of defining and enforcing appropriate security policies. This is, among other things, due to the fact that the actual order of events in an asynchronous distributed environment is not always defined. In addition, security policies often depend on the actual information exchange among the distributed entities.


In this thesis we study the problem of adapting security policies to distributed environments such as grids and mobile code systems. We define what a global security policy is, and indicate some of the difficulties in translating local policies to the entire distributed environment. Then, we propose efficient and scalable security mechanisms for the enforcement of global security policies in distributed computational systems. These mechanisms are based on multiple instances of execution monitors (smart sandboxes) running on the distributed entities and on efficient security information sharing among them. We show that the subclasses of EM policies enforceable by these mechanisms, contain useful and real live security policies such as global information flow policies.


We provide prototype implementation of the security mechanism capable of defining and enforcing global security policies. This mechanism uses AspectJ to intercept security relevant events before they occur and terminates the execution if a target application is about to violate security policy.