Reduction of Quality (RoQ) Attacks on Dynamic Load Balancers: Vulnerability Assessment and Design Tradeoffs

One key adaptation mechanism often deployed in networking and computing systems is dynamic load balancing. The goal from employing dynamic load balancers is to ensure that the offered load would be judiciously distributed across resources to optimize the overall performance. To that end, this paper discovers and studies new instances of Reduction of Quality (RoQ) attacks that target the dynamic operation of load balancers. Our exposition is focused on a number of load balancing policies that are either employed in current commercial products or have been proposed in literature for future deployment. Through queuing theory analysis, numerical solutions, simulations and Internet experiments, we are able to assess the impact of RoQ attacks through the potency metric. We identify the key factors, such as feedback delay and averaging parameters, that expose the trade-offs between resilience and susceptibility to RoQ attacks. These factors could be used to harden load balancers against RoQ attacks. To the best of our knowledge, this work is the first to study adversarial exploits on the dynamic operation of load balancers.