Search

Stack-based memory corruption vulnerabilities have been exploited, allowing attackers to execute arbitrary code and read/write arbitrary memory. Although several solutions have been proposed to prevent memory errors on the stack, they are either limited to a specific type of attack (either spatial or temporal attacks) or cause significant performance degradation. In this paper, we introduce SaVioR, an efficient and comprehensive stack protection mechanism. The key technique involves randomization of the stack layout to reduce its predictability and exploitability. SaVioR isolates an individual object from spatially and temporally adjacent vulnerable objects and randomizes each object's location, which prevents attackers from predicting the stack layout and thus reduces the likelihood of memory errors being exploited. We implemented SaVioR based on the LLVM compiler framework and applied it to the SPEC CPU2006 benchmarks and real-world applications. Our security evaluation showed that SaVioR provides a high degree of randomness in the stack layout and thus reduces the likelihood of successful exploitation of spatial and temporal memory errors on the stack. Our performance evaluation also demonstrated that it incurs a modest performance overhead (13%) with the SPEC CPU2006 benchmark suite, which improves performance compared to the state-of-the-art stack protection while achieving a comparable security level.

We prepared the monomer PCDA-HP composed of 5-hydroxy-N 1,N 3-bis(pyridin-2-ylmethyl)isophthalamide (HP) as a cadmium ion tweezer and then polymerized them to form a polydiacetylene (PDA)-based sensor (PDA-HP), which displayed selective and sensitive colorimetric and fluorometric change upon addition of a cadmium ion (Cd2+) at both pH 7.4 and 6.8. The PDA-HP polymer was highly selective for Cd2+ over other metal ions with colorimetric change. In addition, the PDA-HP chemosensor also showed a red fluorescence change in the presence of Cd2+ at both pH 7.4 and 6.8. Naked-eye detection of Cd2+ was accomplished in an aqueous solution through a PDA-based sensor system. Finally, the lowest energy structure of an HP chelator was obtained by the crystal structure and density functional theory (DFT) calculations.

In this study, we report the fabrication of a highly sensitive colorimetric and fluorometric sensor comprising self-assembled polydiacetylene (PDA) liposomes for the measurement of cysteamine concentration. The N-maleimidomethanol (HM) moiety was used as the Michael addition acceptor, which reacts with the thiol groups in cysteamine to generate maleimide–thiol conjugation resulting in the conformational transition of the conjugated backbone. Furthermore, this chemosensor system displays a clear blue-to-red colorimetric transition in the presence of cysteamine among various biothiols with high selectivity and sensitivity owing to the structural specificity of cysteamine. The resulting PDA solutions were analyzed via FE-SEM, UV-vis, fluorescence and Raman spectroscopy, and chromoisomerism for naked-eye visualization. This chemosensor provides a convenient method for the detection of cysteamine in aqueous solution and in real samples.

ARM TrustZone is widely used to provide a Trusted Execution Environment (TEE) for mobile devices. However, the use of TrustZone is limited because TrustZone resources are only available for some pre-authorized applications. In other words, only alliances of the TrustZone OS vendors and device manufacturers can use TrustZone to secure their services. To help overcome this problem, we designed the PrivateZone framework to enable individual developers to utilize TrustZone resources. Using PrivateZone, developers can run Security Critical Logics (SCL) in a Private Execution Environment (PrEE). The advantage of PrivateZone is its leveraging of TrustZone resources without undermining the security of existing services in the TEE. To guarantee this, PrivateZone creates a PrEE using a memory region that is isolated from both the Rich Execution Environment (REE) and TEE. In this paper, we describe the design and implementation of PrivateZone. The prototype of PrivateZone was implemented on an Arndale board with a Cortex-A15 dual-core processor. We built PrivateZone by exploring both security and virtualization extensions of the ARM architecture. To illustrate the usage and the efficacy of PrivateZone, we developed an Android application based on PrivateZone framework, and evaluated the performance overhead imposed on the OS in the REE and SCLs in the PrEE.

Background: Coronal shear fractures of the distal humerus have recently been identified as a “new” type of fracture. Ring and colleagues proposed a classification for this fracture with 5 increasingly complex subtypes. The purpose of this retrospective study is to classify the patterns of articular shear fractures of the distal part of the humerus, according to Ring’s classification, and to analyze the results of the surgical treatments. Method: Thirteen patients with a mean age of 59 (15-88) years underwent operative treatment and were then followed for an average of 21 (12-30) months. All but 2, treated with total elbow arthroplasty, underwent open reduction and internal fixation (ORIF). Results: According to Ring’s classification, there were three type 2, two type 3, five type 4, and three type 5. Average Mayo Elbow Performance Score was 85 (60-100): 5 patients had excellent, 4 had good, and 4 had fair results. Fracture union was achieved in all but 1. The average arc of motion was 103 with an average flexion contracture of 19. In the analysis of the ORIF group, the patients presenting fracture of the posterior aspect of the lateral column showed worse results than those that were not. It was the same for the patient presenting fracture of the posterior trochlea. A precise recognition of these fracture patterns is useful in surgical decision making and choice of surgical technique. Our results suggest that the type of fracture involvement with posterior aspect of trochlea or capitellum can make poor clinical outcomes.