Helix++: A platform for efficiently securing software

The open-source Helix++ project improves the security posture of computing platforms by applying cutting-edge cybersecurity techniques to diversify and harden software automatically. A distinguishing feature of Helix++ is that it does not require source code or build artifacts; it operates directly on software in binary form--even stripped executables and libraries. This feature is key as rebuilding applications from source is a time-consuming and often frustrating process. Diversification breaks the software monoculture and makes attacks harder to execute as information needed for a successful attack will have changed unpredictably. Diversification also forces attackers to customize an attack for each target instead of attackers crafting an exploit that works reliably on all similarly configured targets. Hardening directly targets key attack classes. The combination of diversity and hardening provides defense-in-depth, as well as a moving target defense, to secure the Nation's cyber infrastructure.Comment: 4 pages, 1 figure, white pape

Same Coverage, Less Bloat: Accelerating Binary-only Fuzzing with Coverage-preserving Coverage-guided Tracing

Coverage-guided fuzzing's aggressive, high-volume testing has helped reveal tens of thousands of software security flaws. While executing billions of test cases mandates fast code coverage tracing, the nature of binary-only targets leads to reduced tracing performance. A recent advancement in binary fuzzing performance is Coverage-guided Tracing (CGT), which brings orders-of-magnitude gains in throughput by restricting the expense of coverage tracing to only when new coverage is guaranteed. Unfortunately, CGT suits only a basic block coverage granularity -- yet most fuzzers require finer-grain coverage metrics: edge coverage and hit counts. It is this limitation which prohibits nearly all of today's state-of-the-art fuzzers from attaining the performance benefits of CGT. This paper tackles the challenges of adapting CGT to fuzzing's most ubiquitous coverage metrics. We introduce and implement a suite of enhancements that expand CGT's introspection to fuzzing's most common code coverage metrics, while maintaining its orders-of-magnitude speedup over conventional always-on coverage tracing. We evaluate their trade-offs with respect to fuzzing performance and effectiveness across 12 diverse real-world binaries (8 open- and 4 closed-source). On average, our coverage-preserving CGT attains near-identical speed to the present block-coverage-only CGT, UnTracer; and outperforms leading binary- and source-level coverage tracers QEMU, Dyninst, RetroWrite, and AFL-Clang by 2-24x, finding more bugs in less time.Comment: CCS '21: Proceedings of the 2021 ACM SIGSAC Conference on Computer and Communications Securit

IMECE2003-44104 SIMULATION AND BOGIE TESTING OF A NEW CABLE BARRIER TERMINAL

ABSTRACT Roadside barriers of various designs are extensively used for the purpose of shielding obstacles along the road from impact with errant vehicles. One commonly applied roadside barrier system is a cable system, consisting of three steel cables supported by weak steel posts. Due to an increase in the use of cable systems, a tangent to the roadway, as opposed to flared away from the roadway, crashworthy end terminal has been designed by the Midwest Roadside Safety Facility. The design goal was to effectively disengage the pre-tensioned cables at the end anchor point when impacted on the end by a vehicle, allowing the vehicle to pass through the system virtually unobstructed. It is the objective of this study to help evaluate the new design through bogie testing and nonlinear finite element analysis using LS-DYNA. Based on bogie test results and detailed analysis of the simulation results, it was concluded that the new cable end terminal was ready for full-scale crash testing. INTRODUCTION Roadside barriers of various designs are extensively used for the purpose of shielding obstacles along the road from impact with errant vehicles. One commonly applied roadside barrier system is the 3-strand cable system. This system consists of three steel cables supported by weak steel posts. The steel cables are pre-tensioned with a specified initial load, and are anchored at both ends of the system. When an errant vehicle obliquely impacts the 3-strand cable system, sufficient tension is developed within the cables to redirect the vehicle, effectively shielding the roadside hazard and increasing the safety of the vehicle operator. The weak steel posts supporting the cables offer very little resistance to the impacting vehicle. Due to the likelihood of a longitudinal impact with the end of the 3-strand cable system, a crashworthy end terminal has been designed by the Midwest Roadside Safety Facility (MwRSF). The design goal was to effectively disengage the pre-tensioned cables at the end anchor point upon impact with a vehicle, allowing the vehicle to pass through the system virtually unobstructed. To assist in the development of the 3-strand cable system end terminal, the CTB-4 bogie crash test was conducted. It is the objective of this study to simulate the cable terminal bogie test CTB-4 using LS-DYNA, a nonlinear finite element analysis code (1), and validate the simulation results with that of the physical test

BRIDGE RAILS AND TRANSITIONS FOR PEDESTRIAN PROTECTION

It is desirable to protect pedestrians on bridges from motor vehicles. However, transition problems arise at the ends of bridges where the bridge rail, bridge rail end treatment, and pedestrian walkway compete for the limited available space. The objective of this study was to identify the most common scenarios in which the protection of pedestrians on bridges is desirable, and then to develop bridge rail and bridge rail end treatment configurations to accommodate those situations. The objective was achieved by performing a field investigation, a survey of state transportation agencies, and a literature review. Recommendations for the placement and general design of standard barrier configurations have been provided in the form of thirteen generalized site drawings. The barrier configurations outlined within this report were based on NCHRP Report No. 350 approved hardware, roadside hardware meeting prior safety standards, hardware believed to provide moderate safety, hardware currently under development, and sound engineering judgement. Therefore, the barrier configurations recommended herein are not equivalent in terms of the level of pedestrian safety provided. As a result, sound engineering judgement is required when determining which barrier configuration to implement for providing pedestrian protection on and near the ends of bridges

Efficient Code Generation in a Region-based Dynamic Binary Translator

Region-based JIT compilation operates on translation units comprising multiple basic blocks and, possibly cyclic or conditional, control flow between these. It promises to reconcile aggressive code optimisation and low compilation latency in performance-critical dynamic binary translators. Whilst various region selection schemes and isolated code optimisation techniques have been investigated it remains unclear how to best exploit such regions for efficient code generation. Complex interactions with indirect branch tables and translation caches can have adverse effects on performance if not considered carefully. In this paper we present a complete code generation strategy for a region-based dynamic binary translator, which exploits branch type and control flow profiling information to improve code quality for the common case. We demonstrate that using our code generation strategy a competitive region-based dynamic compiler can be built on top of the LLVM JIT compilation framework. For the ARM-V5T target ISA and SPEC CPU 2006 benchmarks we achieve execution rates of, on average, 867 MIPS and up to 1323 MIPS on a standard X86 host machine, outperforming state-of-the-art QEMU-ARM by delivering a speedup of 264%

Tubulin isoform composition tunes microtubule dynamics

Microtubules polymerize and depolymerize stochastically, a behavior essential for cell division, motility and differentiation. While many studies advanced our understanding of how microtubule-associated proteins tune microtubule dynamics in trans, we have yet to understand how tubulin genetic diversity regulates microtubule functions. The majority of in vitro dynamics studies are performed with tubulin purified from brain tissue. This preparation is not representative of tubulin found in many cell types. Here we report the 4.2Å cryo-EM structure and in vitro dynamics parameters of α1B/βI+βIVb microtubules assembled from tubulin purified from a human embryonic kidney cell line with isoform composition characteristic of fibroblasts and many immortalized cell lines. We find that these microtubules grow faster and transition to depolymerization less frequently compared to brain microtubules. Cryo-EM reveals that the dynamic ends of α1B/βI+βIVb microtubules are less tapered and that these tubulin heterodimers display lower curvatures. Interestingly, analysis of EB1 distributions at dynamic ends suggests no differences in GTP cap sizes. Lastly, we show that the addition of recombinant α1A/βIII tubulin, a neuronal isotype overexpressed in many tumors, proportionally tunes the dynamics of α1B/βI+βIVb microtubules. Our study is an important step towards understanding how tubulin isoform composition tunes microtubule dynamics

Effect of SGLT2 inhibitors on stroke and atrial fibrillation in diabetic kidney disease: Results from the CREDENCE trial and meta-analysis

BACKGROUND AND PURPOSE: Chronic kidney disease with reduced estimated glomerular filtration rate or elevated albuminuria increases risk for ischemic and hemorrhagic stroke. This study assessed the effects of sodium glucose cotransporter 2 inhibitors (SGLT2i) on stroke and atrial fibrillation/flutter (AF/AFL) from CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation) and a meta-Analysis of large cardiovascular outcome trials (CVOTs) of SGLT2i in type 2 diabetes mellitus. METHODS: CREDENCE randomized 4401 participants with type 2 diabetes mellitus and chronic kidney disease to canagliflozin or placebo. Post hoc, we estimated effects on fatal or nonfatal stroke, stroke subtypes, and intermediate markers of stroke risk including AF/AFL. Stroke and AF/AFL data from 3 other completed large CVOTs and CREDENCE were pooled using random-effects meta-Analysis. RESULTS: In CREDENCE, 142 participants experienced a stroke during follow-up (10.9/1000 patient-years with canagliflozin, 14.2/1000 patient-years with placebo; hazard ratio [HR], 0.77 [95% CI, 0.55-1.08]). Effects by stroke subtypes were: ischemic (HR, 0.88 [95% CI, 0.61-1.28]; n=111), hemorrhagic (HR, 0.50 [95% CI, 0.19-1.32]; n=18), and undetermined (HR, 0.54 [95% CI, 0.20-1.46]; n=17). There was no clear effect on AF/AFL (HR, 0.76 [95% CI, 0.53-1.10]; n=115). The overall effects in the 4 CVOTs combined were: Total stroke (HRpooled, 0.96 [95% CI, 0.82-1.12]), ischemic stroke (HRpooled, 1.01 [95% CI, 0.89-1.14]), hemorrhagic stroke (HRpooled, 0.50 [95% CI, 0.30-0.83]), undetermined stroke (HRpooled, 0.86 [95% CI, 0.49-1.51]), and AF/AFL (HRpooled, 0.81 [95% CI, 0.71-0.93]). There was evidence that SGLT2i effects on total stroke varied by baseline estimated glomerular filtration rate (P=0.01), with protection in the lowest estimated glomerular filtration rate (45 mL/min/1.73 m2]) subgroup (HRpooled, 0.50 [95% CI, 0.31-0.79]). CONCLUSIONS: Although we found no clear effect of SGLT2i on total stroke in CREDENCE or across trials combined, there was some evidence of benefit in preventing hemorrhagic stroke and AF/AFL, as well as total stroke for those with lowest estimated glomerular filtration rate. Future research should focus on confirming these data and exploring potential mechanisms

Canagliflozin and Renal Outcomes in Type 2 Diabetes and Nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to 300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m 2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to &lt;90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], &gt;300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of &lt;15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P&lt;0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P&lt;0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Petite Amateur Navy Satellite (PANSAT)

SEE ParentDocumentRecord|Ntt=19940004512 "USRA, NASA(USRA University Advanced Design Program Fifth Annual Summer Conference"; p. p 111-121The Naval Postgraduate School's (NPS) Space Systems Academic Group (SSAG) is designing and developing a small communications satellite for launch aboard the shuttle as a complex autonomous payload (CAP). The objectives of PANSAT are three-fold. First, PANSAT will provide an ideal educational tool for the officer students at NPS supporting Space Systems Engineering and Space Systems Operations with hands-on hardware development. Second, the satellite will provide digital store-and-forward communications, or packet radio, for the amateur radio community. The third objective is to provide a low-cost, space-based platform for small experiments. PANSAT will be launched from the shuttle at a nominal altitude of 200 n.m. and an inclination of at least 37 degrees. The satellite weight is 150 lbs. Since there is no attitude control, eight dipole whip antennas will be used to provide isotropic ground coverage for communications. FM digital communications will be used with up-link and down-link on a single frequency in the amateur band of 437.25 MHz. A maximum 50 kHz of bandwidth is envisioned for the satellite. The expected lifetime of the satellite is 1 1/2 to 2 years before atmospheric reentry. The PANSAT design consists of the following: communications subsystem (COMM); computer, or data processor and sequencer (DP&amp;S); power subsystem; structure subsystem; and experiment payload.Approved for public release; distribution is unlimited