Abstract-Vulnerabilities in Android kernel give opportunity for attacker to damage the system. Privilege escalation is one of the most dangerous attacks, as it helps attacker to gain root privilege by exploiting kernel vulnerabilities. Mitigation technologies, static detection methods and dynamic defense methods have been suggested to prevent privilege escalation attack, but they still have some disadvantages. In this paper, we propose an improved method named PtmxGuard to enhance Android kernel and defeat privilege escalation attack. We focus on a typical attack pattern that attacker hijacks the control flow of Android kernel to modify process credentials by corrupting critical global function pointers. PtmxGuard enforces Code Pointer Integrity to Android kernel, checks the accuracy and reliability of those pointers when they're triggered by related system calls, and intercepts the system calls when attack activities are detected. Experiment result demonstrates that PtmxGuard can defense privilege escalation attack effectively.
This paper describes the background and significance of the whole process state monitoring of express logistics in the three aspects of environment, society and economy, then introduces the current status of the tracking and monitoring of logistics process at home and abroad, and proposes the method of full-process condition monitoring and evaluation method for express logistics based on multi-information fusion and intelligent identification, The content of the method mainly includes: collecting data based on various information collection methods such as sensors, extracting and identifying the characteristics of expressive behavior through the algorithm and quantitative evaluation of the whole process express logistics status.finally, Finally, the paper summarizes the whole system-based method of multi-information fusion and intelligent identification of the whole logistics process monitoring and evaluation, and explains the follow-up work direction and content.
A partial Motzkin path is a path from (0, 0) to (n, k) in the XOY -plane that does not go below the X-axis and consists of up steps U = (1, 1), down steps D = (1, −1) and horizontal steps H = (1, 0). A weighted partial Motzkin path is a partial Motzkin path with the weight assignment that all up steps and down steps are weighted by 1, the horizontal steps are endowed with a weight x if they are lying on X-axis, and endowed with a weight y if they are not lying on X-axis. Denote by M n,k (x, y) to be the weight function of all weighted partial Motzkin paths from (0, 0) to (n, k), and M = (M n,k (x, y)) n≥k≥0 to be the infinite lower triangular matrices. In this paper, we consider the sums of minors of second order of the matrix M, and obtain a lot of interesting determinant identities related to M, which are proved by bijections using weighted partial Motzkin paths. When the weight parameters (x, y) are specialized, several new identities are obtained related to some classical sequences involving Catalan numbers. Besides, in the alternating cases we also give some new explicit formulas for Catalan numbers.
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