SlowFuzz: Automated Domain-Independent Detection of Algorithmic Complexity Vulnerabilities

Algorithmic complexity vulnerabilities occur when the worst-case time/space complexity of an application is significantly higher than the respective average case for particular user-controlled inputs. When such conditions are met, an attacker can launch Denial-of-Service attacks against a vulnerable application by providing inputs that trigger the worst-case behavior. Such attacks have been known to have serious effects on production systems, take down entire websites, or lead to bypasses of Web Application Firewalls. Unfortunately, existing detection mechanisms for algorithmic complexity vulnerabilities are domain-specific and often require significant manual effort. In this paper, we design, implement, and evaluate SlowFuzz, a domain-independent framework for automatically finding algorithmic complexity vulnerabilities. SlowFuzz automatically finds inputs that trigger worst-case algorithmic behavior in the tested binary. SlowFuzz uses resource-usage-guided evolutionary search techniques to automatically find inputs that maximize computational resource utilization for a given application.Comment: ACM CCS '17, October 30-November 3, 2017, Dallas, TX, US

X - Ray Flares and Their Connection With Prompt Emission in GRBs

We use a wavelet technique to investigate the time variations in the light curves from a sample of GRBs detected by Fermi and Swift. We focus primarily on the behavior of the flaring region of Swift-XRT light curves in order to explore connections between variability time scales and pulse parameters (such as rise and decay times, widths, strengths, and separation distributions) and spectral lags. Tight correlations between some of these temporal features suggest a common origin for the production of X-ray flares and the prompt emission.Comment: 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 15 in eConf Proceedings C130414

Nonequilibrium phase transition in a radiation-driven Josephson junction

We predict that a nonequilibrium phase transition, analogous to optical bistability, occurs when coherent radiation is applied to an unbiased Josephson junction with an external resistance across it. The order parameter is the self-consistently developed dc voltage, and the drive parameter is the applied radiation intensity. The order parameter exhibits jump and hysteresis behavior characteristic of a first-order phase transition. The size of the hysteresis region can be tuned by varying the resistance. An approach based on the Fokker-Planck equation is adopted. The extremum of the stationary probability yields the self-consistency equation for the mean-field order parameter. Relaxation and decay times are calculated, the decay times being identified with the first passage time. Estimates of parameters show that the bistable regime could be experimentally accessible

Indications of superconductivity in doped highly oriented pyrolytic graphite

We have observed possible superconductivity using standard resistance vs. temperature techniques in phosphorous ion implanted Highly Oriented Pyrolytic Graphite. The onset appears to be above 100 K and quenching by an applied magnetic field has been observed. The four initial boron implanted samples showed no signs of becoming superconductive whereas all four initial and eight subsequent samples that were implanted with phosphorous showed at least some sign of the existence of small amounts of the possibly superconducting phases. The observed onset temperature is dependent on both the number of electron donors present and the amount of damage done to the graphene sub-layers in the Highly Oriented Pyrolytic Graphite samples. As a result the data appears to suggest that the potential for far higher onset temperatures in un-damaged doped graphite exists.Comment: 7 pages, 1 table, 5 figures, 11 references, Acknowledgments section was correcte

Exponent behavior at a dissipative phase transition of a driven Josephson junction

Static and dynamic critical exponents and a set of spinodal exponents are calculated within a mean-field approximation for the case of a driven Josephson junction undergoing a nonequilibrium phase transition. These universal exponents obey the exponent relations obtained from scaling-for-equilibrium phase transitions. The exponents are directly related to experimental observables such as the junction voltage, its noise bandwidth, and the Josephson radiation linewidth

Radiation-induced bistability in Josephson junctions

It is predicted that a nonequilibrium first-order phase transition analogous to optical bistability can occur when external coherent radiation is applied to a suitably prepared Josephson junction with an external resistance across it. The size of the hysteresis region can be tuned by varying the resistance

Observability of hysteresis in first-order equilibrium and nonequilibrium phase transitions

The general conditions under which a system undergoing a first-order phase transition will exhibit hysteresis behavior, rather than simple jump behavior, are obtained. These are expressed in terms of the intrinsic time scales of the system and the time scale of variation of the control parameter. The size of the critical region is estimated. Estimates of the characteristic times are made for some equilibrium and nonequilibrium systems to show hysteresis behavior

Learning Conditional Distributions using Mixtures of Truncated Basis Functions

Mixtures of Truncated Basis Functions (MoTBFs) have recently been proposed for modelling univariate and joint distributions in hybrid Bayesian networks. In this paper we analyse the problem of learning conditional MoTBF distributions from data. Our approach utilizes a new technique for learning joint MoTBF densities, then propose a method for using these to generate the conditional distributions. The main contribution of this work is conveyed through an empirical investigation into the properties of the new learning procedure, where we also compare the merits of our approach to those obtained by other proposals