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

PMI: A Delta Psi(m) Independent Pharmacological Regulator of Mitophagy

Mitophagy is central to mitochondrial and cellular homeostasis and operates via the PINK1/Parkin pathway targeting mitochondria devoid of membrane potential (ΔΨm) to autophagosomes. Although mitophagy is recognized as a fundamental cellular process, selective pharmacologic modulators of mitophagy are almost nonexistent. We developed a compound that increases the expression and signaling of the autophagic adaptor molecule P62/SQSTM1 and forces mitochondria into autophagy. The compound, P62-mediated mitophagy inducer (PMI), activates mitophagy without recruiting Parkin or collapsing ΔΨm and retains activity in cells devoid of a fully functional PINK1/Parkin pathway. PMI drives mitochondria to a process of quality control without compromising the bio-energetic competence of the whole network while exposing just those organelles to be recycled. Thus, PMI circumvents the toxicity and some of the nonspecific effects associated with the abrupt dissipation of ΔΨm by ionophores routinely used to induce mitophagy and represents a prototype pharmacological tool to investigate the molecular mechanisms of mitophagy

Structure and evolution of the intracratonic Congo Basin

Surface wave tomography, heat flow, and crustal thickness measurements have demonstrated that the thickness of the continental lithosphere varies by at least a factor of 2. Since the thermal time constant of the lithosphere depends upon the square of its thickness, subsidence records of extensional sedimentary basins offer a potential way of extending these observations into the past. Here we examine the Congo basin, a large and iconic intracratonic sedimentary basin in Central Africa. This roughly circular basin covers an area in excess of 1.4 × 106 km2 with more than 5 km thickness of sedimentary rocks, the oldest parts of which are late Precambrian in age. First, we assess the thickness of the lithosphere. We have estimated its thickness across Africa using maps of shear wave velocity obtained by inversion of fundamental and higher-mode surface waveforms. The Congo Basin sits on 220 ± 30 km thick lithosphere and appears to be part of a southern core to the continent encompassing both Archean cratons and Proterozoic mobile belts. This thickness is consistent with published estimates from kimberlites. Reappraisal of legacy seismic reflection images demonstrates that the sedimentary section is underlain by a Late Precambrian rift zone and that the basin is still subsiding today. Subsidence modeling of two deep wells is consistent with uniform extension and cooling of the lithosphere by a factor of 1.2 during latest Precambrian and Cambrian time; we argue that the exceptional 0.55 Ga history of the basin is a direct consequence of the lithospheric thermal time constant being a factor of 4 longer than normal. Today, the basin coincides with a long-wavelength −30 to −40 mGal gravity anomaly. We interpret this gravity anomaly as the surficial manifestation of 400–600 m of recent mantle convective drawdown in response to the onset of upwelling plumes around the flanks of the southern African continent. The alternative explanation, that it is the static manifestation of locally thick lithosphere, is inconsistent with global trends of mantle density depletion. Our interpretation is consistent with fast seismic velocities observed throughout the sublithospheric upper mantle underneath the basin and recent geodynamic modeling

Deformation of vortex patches by boundaries

The deformation of two-dimensional vortex patches in the vicinity of fluid boundaries is investigated. The presence of a boundary causes an initially circular patch of uniform vorticity to deform. Sufficiently far away from the boundary, the deformed shape is well approximated by an ellipse. This leading order elliptical deformation is investigated via the elliptic moment model of Melander, Zabusky & Styczek [M. V. Melander, N. J. Zabusky & A. S. Styczek, J. Fluid. Mech., 167, 95 (1986)]. When the boundary is straight, the centre of the elliptic patch remains at a constant distance from the boundary, and the motion is integrable. Furthermore, since the straining flow acting on the patch is constant in time, the problem is that of an elliptic vortex patch in constant strain, which was analysed by Kida [S. Kida, J. Phys. Soc. Japan, 50, 3517 (1981)]. For more complicated boundary shapes, such as a square corner, the motion is no longer integrable. Instead, there is an adiabatic invariant for the motion. This adiabatic invariant arises due to the separation in times scales between the relatively rapid time scale associated with the rotation of the patch and the slower time scale associated with the self-advection of the patch along the boundary. The interaction of a vortex patch with a circular island is also considered. Without a background flow, conservation of angular impulse implies that the motion is again integrable. The addition of an irrotational flow past the island can drive the patch towards the boundary, leading to the possibility of large deformations and breakup.Comment: 19 pages, 16 figure

Seed Size and Its Relationship with Crop Establishment, Productivity and Nutritive Value in Genotypes of Maize for Silage

For a high dry matter (DM) yield of forage maize an adequate population of plants is required, which is related to germination, vigour, and seed size (Ellis, 1992). The objective of the present study was to investigate seed size and its relationship to establishment, productive and nutritional potential of silage maize, which has not before been reported in the literature

Noise storm continua: power estimates for electron acceleration

We use a generic stochastic acceleration formalism to examine the power $L_{\rm in}$ (${\rm erg s^{-1}}$) input to nonthermal electrons that cause noise storm continuum emission. The analytical approach includes the derivation of the Green's function for a general second-order Fermi process, and its application to obtain the particular solution for the nonthermal electron distribution resulting from the acceleration of a Maxwellian source in the corona. We compare $L_{\rm in}$ with the power $L_{\rm out}$ observed in noise storm radiation. Using typical values for the various parameters, we find that $L_{\rm in} \sim 10^{23-26}$ ${\rm erg s^{-1}}$, yielding an efficiency estimate $\eta \equiv L_{\rm out}/L_{\rm in}$ in the range 10^{-10} \lsim \eta \lsim 10^{-6} for this nonthermal acceleration/radiation process. These results reflect the efficiency of the overall process, starting from electron acceleration and culminating in the observed noise storm emission.Comment: Accepted for publication in Solar Physic

Molecular and Phenotypic Characterization of Methicillin-Resistant \u3ci\u3eStaphylococcus aureus\u3c/i\u3e Isolates Causing Bacteremia At a Major Hospital in Southern Mississippi

Staphylococcus aureus is the predominant cause of bacteremia worldwide. We assessed the molecular epidemiology and antibiotic resistance of methicillin-resistant S aureus isolates causing bacteremia in southern Mississippi. Diverse genetic backgrounds in terms of staphylococcal cassette chromosome mec, pulsed-field gel electrophoresis, and multilocus sequence typing types of methicillin-resistant S aureus were identified as causing bacteremia in Mississippi. A strong association of Panton-Valentine leukocidin genes with elevated vancomycin minimum inhibitory concentration is one of the important findings of our study

Identifying Behavioral Health Needs of Individuals Screened at the Booking Counter of Montgomery County Jail

Background: Many of the individuals who are released from incarceration are re-arrested and re-incarcerated within three years of release. Challenges that predispose individuals to re-arrest and re-incarceration include lack of education, employment opportunities, decent affordable housing, and treatment for substance use disorders (SUD) and/or mental illness. This report summarizes the behavioral health needs of newly arrested individuals in Montgomery County, Ohio.Methods: For this project, 4,809 adult individuals arrested for non-violent crimes received behavioral health screening and case management at booking in the Montgomery County Jail. Criminogenic assessment using the Risk-Needs-Responsivity (RNR) tool was conducted with 484 arrestees. Descriptive statistics and chi square statistics were calculated for gender, race, referrals made, education level, employment status, housing status, alcohol and other drug use, and mental health status.Results: As a group, the arrestees were undereducated, underemployed, and homeless. Based on RNR assessment, 67% had an SUD,and 60% required mental health treatment. Significant gender and racial differences were found among the arrestees, with womensignificantly more likely to have SUD and mental health issues.Conclusions: Individuals arrested and booked into the Montgomery County Jail experience a complex interaction among mental health, poly-substance use, medical, employment, and housing needs that must be addressed in a comprehensive and coordinated funding manner. This interactive complexity of issues demand a response from an integrated service delivery system that would best benefit the person served and the community