Sistema ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa


Tesi etd-05222010-155815

Tipo di tesi
Tesi di dottorato di ricerca
Measuring the Semantic Integrity of a Process Self
Settore scientifico disciplinare
Corso di studi
tutor Prof. Baiardi, Fabrizio
Parole chiave
  • virtual communities
  • semantic integrity
  • security
  • remote attestation
  • process self
  • IDS
  • code obfuscation
  • virtual machines
Data inizio appello
Riassunto analitico
The focus of the thesis is the definition of a framework to protect a process from attacks against the process self, i.e. attacks that alter the expected behavior of the process, by integrating static analysis and run-time monitoring. The static analysis of the program returns a description of the process self that consists of a context-free grammar, which defines the legal system call traces, and a set of invariants on process variables that hold when a system call is issued. Run-time monitoring assures the semantic integrity of the process by checking that its behavior is coherent with the process self returned by the static analysis. The proposed framework can also cover kernel integrity to protect the process from attacks from the kernel-level.

The implementation of the run-time monitoring is based upon introspection, a technique that analyzes the state of a computer to rebuild and check the consistency of kernel or user-level data structures. The ability of observing the run-time values of variables reduces the complexity of the static analysis and increases the amount of information that can be extracted on the run-time behavior of the process. To achieve transparency of the controls for the process while avoiding the introduction of special purpose hardware units that access the memory, the architecture of the run-time monitoring adopts virtualization technology and introduces two virtual machines, the monitored and the introspection virtual machines. This approach increases the overall robustness because a distinct virtual machine, the introspection virtual machine, applies introspection in a transparent way both to verify the kernel integrity and to retrieve the status of the process to check the process self.

After presenting the framework and its implementation, the thesis discusses some of its applications to increase the security of a computer network. The first application of the proposed framework is the remote attestation of the semantic integrity of a process. Then, the thesis describes a set of extensions to the framework to protect a process from physical attacks by running an obfuscated version of the process code. Finally, the thesis generalizes the framework to support the efficient sharing of an information infrastructure among users and applications with distinct security and reliability requirements by introducing highly parallel overlays.