1. A method for behavior tracking in a mobile device using behavioral vectors, the method comprising: determining in a processor of the mobile device a feature that is to be observed in the mobile device in order to identify a suspicious mobile device behavior, adaptively observing the determined feature in the mobile device by collecting behavior information from an instrumented component that is associated with the determined feature; generating a vector data structure that describes the collected behavior information via a plurality of numbers; and performing behavior analysis operations that include applying a classifier model that includes decision nodes to the vector data structure to identify the suspicious mobile device behavior.