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A new set of benchmarks has been developed for the performance evaluation of highly parallel supercomput-

No abstract

A continuous adjoint approach for obtaining sensitivity derivatives on unstructured grids is developed and analyzed. The derivation of the costate equations is presented, and a second-order accurate discretization method is described. The relationship between the continuous formulation and a discrete formulation is explored for inviscid, as well as for viscous¯ow. Several limitations in a strict adherence to the continuous approach are uncovered, and an approach that circumvents these diculties is presented. The issue of grid sensitivities, which do not arise naturally in the continuous formulation, is investigated and is observed to be of importance when dealing with geometric singularities. A method is described for modifying inviscid and viscous meshes during the design cycle to accommodate changes in the surface shape. The accuracy of the sensitivity derivatives is established by comparing with ®nitedierence gradients and several design examples are presented.

A new set of benchmarks has been developed for the performance evaluation of highly parallel supercomputers. These benchmarks consist of ve \parallel kernel" benchmarks and three \simulated application" benchmarks. Together they mimic the computation and data movement c haracteristics of large scale computational uid dynamics applications.The principal distinguishing feature of these benchmarks is their \pencil and paper" speci cation | all details of these benchmarks are speci ed only algorithmically. In this way m a n y of the di culties associated with conventional benchmarking approaches on highly parallel systems are avoided.

In this paper, we present HOLMES, a system that implements a new approach to the detection of Advanced and Persistent Threats (APTs). HOLMES is inspired by several case studies of real-world APTs that highlight some common goals of APT actors. In a nutshell, HOLMES aims to produce a detection signal that indicates the presence of a coordinated set of activities that are part of an APT campaign. One of the main challenges addressed by our approach involves developing a suite of techniques that make the detection signal robust and reliable. At a high-level, the techniques we develop effectively leverage the correlation between suspicious information flows that arise during an attacker campaign. In addition to its detection capability, HOLMES is also able to generate a high-level graph that summarizes the attacker's actions in real-time. This graph can be used by an analyst for an effective cyber response. An evaluation of our approach against some real-world APTs indicates that HOLMES can detect APT campaigns with high precision and low false alarm rate. The compact high-level graphs produced by HOLMES effectively summarizes an ongoing attack campaign and can assist real-time cyber-response operations.

A continuous adjoint approach for obtaining sensitivity derivatives on unstructured grids is developed and analyzed. The derivation of the costate equations is presented, and a second-order accurate discretization method is described. The relationship between the continuous formulation and a discrete formulation is explored for inviscid, as well as for viscous¯ow. Several limitations in a strict adherence to the continuous approach are uncovered, and an approach that circumvents these diculties is presented. The issue of grid sensitivities, which do not arise naturally in the continuous formulation, is investigated and is observed to be of importance when dealing with geometric singularities. A method is described for modifying inviscid and viscous meshes during the design cycle to accommodate changes in the surface shape. The accuracy of the sensitivity derivatives is established by comparing with ®nitedierence gradients and several design examples are presented.

Parameter tampering attacks are dangerous to a web application whose server fails to replicate the validation of user-supplied data that is performed by the client in web forms. Malicious users who circumvent the client can capitalize on the missing server validation. In this paper, we provide a formal description of parameter tampering vulnerabilities and a high level approach for their detection. We specialize this high level approach to develop complementary detection solutions in two interesting settings: blackbox (only analyze client-side code in web forms) and whitebox (also analyze server-side code that processes submitted web forms). This paper presents interesting challenges encountered in realizing the high level approach for each setting and novel technical contributions that address these challenges. We also contrast utility, difficulties and effectiveness issues in both settings and provide a quantitative comparison of results. Our experiments with real world and open source applications demonstrate that parameter tampering vulnerabilities are prolific (total 47 in 9 applications), and their exploitation can have serious consequences including unauthorized transactions, account hijacking and financial losses. We conclude this paper with a discussion on countermeasures for parameter tampering attacks and present a detailed survey of existing defenses and their suitability.