Enforcing security policies with runtime monitors

Authors: Khoury, Raphaël
Advisor: Tawbi, Nadia
Abstract: Execution monitoring is an approach that seeks to allow an untrusted code to run safely by observing its execution and reacting if need be to prevent a potential violation of a user-supplied security policy. This method has many promising applications, particularly with respect to the safe execution of mobile code. Academic research on monitoring has generally focused on two questions. The first, relates to the set of policies that can be enforced by monitors under various constraints and the conditions under which this set can be extended. The second question deals with the way to inline a monitor into an untrusted or potentially malicious program in order to produce a new instrumented program that provably respects the desired security policy. This study builds on the two strands of research mentioned above and brings new insights to this study. It seeks, in the first place, to increase the scope of monitorable properties by suggesting a new approach of monitor inlining. By drawing on an a priori model of the program’s possible behavior, we develop a monitor that can enforce a strictly larger set of security properties. Furthermore, longstanding research has showed that a monitor that is allowed to transform its input is more powerful than one lacking this ability. Naturally, this ability must be constrained for the enforcement to be meaningful. Otherwise, if the monitor is given too broad a leeway to transform valid and invalid sequences, any property can be enforced, but not in a way that is useful or desirable. In this study, we propose two new enforcement paradigms which capture reasonable restrictions on a monitor’s ability to alter its input. We study the set of properties enforceable if these enforcement paradigms are used and give examples of real-life security policies that can be enforced using our approach.
Document Type: Thèse de doctorat
Issue Date: 2011
Open Access Date: 17 April 2018
Permalink: http://hdl.handle.net/20.500.11794/22394
Grantor: Université Laval
Collection:Thèses et mémoires

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