Reduction-of-quality attacks on adaptation mechanisms
Azer Bestavros, Mina Guirguis · 2007
One important consideration in realizing dependable computing systems and networks is to uncover vulnerabilities in their designs to adversarial attacks. Currently, the designs of these systems employ different forms of adaptation mechanisms in order to optimize their performance by ensuring that desirable properties, such as stability, efficiency and fairness, are not compromised. This thesis discovers and studies a new type of adversarial attacks that target such adaptation mechanisms by exploiting their dynamics of operation--- i.e., the characteristics of their transient behavior. We coin this new breed of adversarial attacks, Reduction of Quality (RoQ) attacks. The premise of RoQ attacks is to keep an adaptive mechanism constantly in a transient state, effectively depriving the system from much of its capacity and significantly reducing its service quality. In this thesis we develop a general control-theoretic framework that provides a unified approach to modeling and vulnerability assessment of the dynamics underlying RoQ exploits. Within this framework, we introduce and formalize the notion of an attack Potency that capitalizes on the attacker's best incentive: maximizing the marginal utility of its attack traffic. Unlike traditional brute-force Denial of Service attacks that aim to take down a system at any cost, RoQ attacks aim to maximize the damage inflicted on a system through consuming an innocuous, small fraction of that system's hijacked capacity. We instantiate our framework using detailed analytical models and associated metrics on a series of adaptation mechanisms that are commonly used in networking protocols, endsystem admission controllers and load balancers. We assess the impact of RoQ attacks using analysis, simulations, and Internet experiments. We identify key factors that expose the tradeoffs between resilience and susceptibility to RoQ attacks. These factors could be used to harden adaptation mechanisms against RoQ exploits, in addition to developing new forms of countermeasures and defense mechanisms.