Power attack defense: securing battery-backed data centers

Battery systems are crucial components for mission-critical data centers. Without secure energy backup, existing under-provisioned data centers are largely unguarded targets for cyber criminals. Particularly for today's scale-out servers, power oversubscription unavoidably taxes a data center's backup energy resources, leaving very little room for dealing with emergency. Besides, the emerging trend towards deploying distributed energy storage architecture causes the associated energy backup of each rack to shrink, making servers vulnerable to power anomalies. As a result, an attacker can generate power peaks to easily crash or disrupt a power-constrained system. This study aims at securing data centers from malicious loads that seek to drain their precious energy storage and overload server racks without prior detection. We term such load as Power Virus (PV) and demonstrate its basic two-phase attacking model and characterize its behaviors on real systems. The PV can learn the victim rack's battery characteristics by disguising as benign loads. Once gaining enough information, the PV can be mutated to generate hidden power spikes that have a high chance to overload the system. To defend against PV, we propose power attack defense (PAD), a novel energy management patch built on lightweight software and hardware mechanisms. PAD not only increases the attacking cost considerably by hiding vulnerable racks from visible spikes, it also strengthens the last line of defense against hidden spikes. Using Google cluster traces we show that PAD can effectively raise the bar of a successful power attack: compared to prior arts, it increases the data center survival time by 1.6~11X and provides better performance guarantee. It enables modern data centers to safely exploit the benefits that power oversubscription may provide, with the slightest cost overhead.