Systems connected to the Internet are highly susceptible to denial-of-service attacks that can compromise service availability, causing damage to customers and providers. Due to errors in the design or coding phases, particular client-server interactions can be made to consume much more resources than necessary easing the success of this kind of attack. To address this issue we propose a new methodology for the detection and identification of local resource-exhaustion vulnerabilities. The methodology also gives a prediction on the necessary effort to exploit a specific vulnerability, useful to support decisions regarding the configuration of a system, in order to sustain a certain attack magnitude. The methodology was implemented in a tool called PREDATOR that is able to automatically generate malicious traffic and to perform post-processing analysis to build accurate resource usage projections on a given target server. The validity of the approach was demonstrated with several sy...