Smart Computer Security Audit: Reinforcement Learning with a Deep Neural Network Approximator

A significant challenge in modern computer security is the growing skill gap as intruder capabilities increase, making it necessary to begin automating elements of penetration testing so analysts can contend with the growing number of cyber threats. In this paper, we attempt to assist human analysts by automating a single host penetration attack. To do so, a smart agent performs different attack sequences to find vulnerabilities in a target system. As it does so, it accumulates knowledge, learns new attack sequences and improves its own internal penetration testing logic. As a result, this agent (AgentPen for simplicity) is able to successfully penetrate hosts it has never interacted with before. A computer security administrator using this tool would receive a comprehensive, automated sequence of actions leading to a security breach, highlighting potential vulnerabilities, and reducing the amount of menial tasks a typical penetration tester would need to execute. To achieve autonomy, we apply an unsupervised machine learning algorithm, Q-learning, with an approximator that incorporates a deep neural network architecture. The security audit itself is modelled as a Markov Decision Process in order to test a number of decisionmaking strategies and compare their convergence to optimality. A series of experimental results is presented to show how this approach can be effectively used to automate penetration testing using a scalable, i.e. not exhaustive, and adaptive approach

A predictive model for risk and trust assessment in cloud computing: taxonomy and analysis for attack pattern detection

Cloud computing environments consist of many entities that have different roles, such as provider and customer, and multiple interactions amongst them. Trust is an essential element to develop confidence-based relationships amongst the various components in such a diverse environment. The current chapter presents the taxonomy of trust models and classification of information sources for trust assessment. Furthermore, it presents the taxonomy of risk factors in cloud computing environment. It analyses further the existing approaches and portrays the potential of enhancing trust development by merging trust assessment and risk assessment methodologies. The aim of the proposed solution is to combine information sources collected from various trust and risk assessment systems deployed in cloud services, with data related to attack patterns. Specifically, the approach suggests a new qualitative solution that could analyse each symptom, indicator, and vulnerability in order to detect the impact and likelihood of attacks directed at cloud computing environments. Therefore, possible implementation of the proposed framework might help to minimise false positive alarms, as well as to improve performance and security, in the cloud computing environment

Cross-Site Scripting (XSS) Detection Integrating Evidences in Multiple Stages

As Cross-Site Scripting (XSS) remains one of the top web security risks, people keep exploring ways to detect such attacks efficiently. So far, existing solutions only focus on the payload in a web request or a response, a single stage of a web transaction. This work proposes a new approach that integrates evidences from both a web request and its response in order to better characterize XSS attacks and separate them from normal web transactions. We first collect complete payloads of XSS and normal web transactions from two databases and extract features from them using the Word2vec technique. Next, we train two Gaussian mixture models (GMM) with these features, one for XSS transaction and one for normal web transactions. These two models can generate two probability scores for a new web transaction, which indicate how similar this web transaction is to XSS and normal traffics respectively. Finally, we put together these two GMM models in classification by combining these two probabilities to further improve detection accuracy

Smart Security Audit: Reinforcement Learning with a Deep Neural Network Approximator

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Program Analysis Based Approaches to Ensure Security and Safety of Emerging Software Platforms

Our smartphones, homes, hospitals, and automobiles are being enhanced with software that provide an unprecedentedly rich set of functionalities, which has created an enormous market for the development of software that run on almost every personal computing devices in a person's daily life, including security- and safety-critical ones. However, the software development support provided by the emerging platforms also raises security risks by allowing untrusted third-party code, which can potentially be buggy, vulnerable or even malicious to control user's device. Moreover, as the Internet-of-Things (IoT) technology is gaining vast adoptions by a wide range of industries, and is penetrating every aspects of people's life, safety risks brought by the open software development support of the emerging IoT platform (e.g., smart home) could bring more severe threat to the well-being of customers than what security vulnerabilities in mobile apps have done to a cell phone user. To address this challenge posed on the software security in emerging domains, my dissertation focuses on the flaws, vulnerabilities and malice in the software developed for platforms in these domains. Specifically, we demonstrate that systematic program analyses of software (1) Lead to an understanding of design and implementation flaws across different platforms that can be leveraged in miscellaneous attacks or causing safety problems; (2) Lead to the development of security mechanisms that limit the potential for these threats.We contribute static and dynamic program analysis techniques for three modern platforms in emerging domains -- smartphone, smart home, and autonomous vehicle. Our app analysis reveals various different vulnerabilities and design flaws on these platforms, and we propose (1) static analysis tool OPAnalyzer to automates the discovery of problems by searching for vulnerable code patterns; (2) dynamic testing tool AutoFuzzer to efficiently produce and capture domain specific issues that are previously undefined; and (3) propose new access control mechanism ContexIoT to strengthen the platform's immunity to the vulnerability and malice in third-party software. Concretely, we first study a vulnerability family caused by the open ports on mobile devices, which allows remote exploitation due to insufficient protection. We devise a tool called OPAnalyzer to perform the first systematic study of open port usage and their security implications on mobile platform, which effectively identify and characterize vulnerable open port usage at scale in popular Android apps. We further identify the lack of context-based access control as a main enabler for such attacks, and begin to seek for defense solution to strengthen the system security. We study the popular smart home platform, and find the existing access control mechanisms to be coarse-grand, insufficient, and undemanding. Taking lessons from previous permission systems, we propose the ContexIoT approach, a context-based permission system for IoT platform that supports third-party app development, which protects the user from vulnerability and malice in these apps through fine-grained identification of context. Finally, we design dynamic fuzzing tool, AutoFuzzer for the testing of self-driving functionalities, which demand very high code quality using improved testing practice combining the state-of-the-art fuzzing techniques with vehicular domain knowledge, and discover problems that lead to crashes in safety-critical software on emerging autonomous vehicle platform.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145845/1/jackjia_1.pd

Framework for Assessing Information System Security Posture Risks

In today’s data-driven world, Information Systems, particularly the ones operating in regulated industries, require comprehensive security frameworks to protect against loss of confidentiality, integrity, or availability of data, whether due to malice, accident or otherwise. Once such a security framework is in place, an organization must constantly monitor and assess the overall compliance of its systems to detect and rectify any issues found. This thesis presents a technique and a supporting toolkit to first model dependencies between security policies (referred to as controls) and, second, devise models that associate risk with policy violations. Third, devise algorithms that propagate risk when one or more policies are found to be non-compliant and fourth, propose a technique that evaluates the overall security posture risk of a system as a function of the non-compliant policies, the affected policies, and the time elapsed since these policy violations discovered but not have been mitigated yet. More specifically, the approach is based on modeling the dependencies between the different controls in the NIST 800.53 framework by compiling a dependency multi-graph, devising a fuzzy-reasoning-based risk assessment technique that traverses the dependency multi-graph and assigns an overall security exposure risk score when one or more controls fail, and finally a technique for identifying the strategies an attacker can use, given the failed controls, and for which an organization should defend itself. This approach allows organizations to obtain a bird’s-eye view of their Information Systems’ cyber security posture and help triage the security control checks by focusing on the most vulnerable parts of their Information System ecosystem

New Anomaly Network Intrusion Detection System in Cloud Environment Based on Optimized Back Propagation Neural Network Using Improved Genetic Algorithm

Cloud computing is distributed architecture, providing computing facilities and storage resource as a service over an open environment (Internet), this lead to different matters related to the security and privacy in cloud computing. Thus, defending network accessible Cloud resources and services from various threats and attacks is of great concern. To address this issue, it is essential to create an efficient and effective Network Intrusion System (NIDS) to detect both outsider and insider intruders with high detection precision in the cloud environment. NIDS has become popular as an important component of the network security infrastructure, which detects malicious activities by monitoring network traffic. In this work, we propose to optimize a very popular soft computing tool widely used for intrusion detection namely, Back Propagation Neural Network (BPNN) using an Improved Genetic Algorithm (IGA). Genetic Algorithm (GA) is improved through optimization strategies, namely Parallel Processing and Fitness Value Hashing, which reduce execution time, convergence time and save processing power. Since,  Learning rate and Momentum term are among the most relevant parameters that impact the performance of BPNN classifier, we have employed IGA to find the optimal or near-optimal values of these two parameters which ensure high detection rate, high accuracy and low false alarm rate. The CloudSim simulator 4.0 and DARPA’s KDD cup datasets 1999 are used for simulation. From the detailed performance analysis, it is clear that the proposed system called “ANIDS BPNN-IGA” (Anomaly NIDS based on BPNN and IGA) outperforms several state-of-art methods and it is more suitable for network anomaly detection