817 resultados para Intrusion Detection, Computer Security, Misuse
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El Malware es una grave amenaza para la seguridad de los sistemas. Con el uso generalizado de la World Wide Web, ha habido un enorme aumento en los ataques de virus, haciendo que la seguridad informática sea esencial para todas las computadoras y se expandan las áreas de investigación sobre los nuevos incidentes que se generan, siendo una de éstas la clasificación del malware. Los “desarrolladores de malware” utilizan nuevas técnicas para generar malware polimórfico reutilizando los malware existentes, por lo cual es necesario agruparlos en familias para estudiar sus características y poder detectar nuevas variantes de los mismos. Este trabajo, además de presentar un detallado estado de la cuestión de la clasificación del malware de ficheros ejecutables PE, presenta un enfoque en el que se mejora el índice de la clasificación de la base de datos de Malware MALICIA utilizando las características estáticas de ficheros ejecutables Imphash y Pehash, utilizando dichas características se realiza un clustering con el algoritmo clustering agresivo el cual se cambia con la clasificación actual mediante el algoritmo de majority voting y la característica icon_label, obteniendo un Precision de 99,15% y un Recall de 99,32% mejorando la clasificación de MALICIA con un F-measure de 99,23%.---ABSTRACT---Malware is a serious threat to the security of systems. With the widespread use of the World Wide Web, there has been a huge increase in virus attacks, making the computer security essential for all computers. Near areas of research have append in this area including classifying malware into families, Malware developers use polymorphism to generate new variants of existing malware. Thus it is crucial to group variants of the same family, to study their characteristics and to detect new variants. This work, in addition to presenting a detailed analysis of the problem of classifying malware PE executable files, presents an approach in which the classification in the Malware database MALICIA is improved by using static characteristics of executable files, namely Imphash and Pehash. Both features are evaluated through clustering real malware with family labels with aggressive clustering algorithm and combining this with the current classification by Majority voting algorithm, obtaining a Precision of 99.15% and a Recall of 99.32%, improving the classification of MALICIA with an F-measure of 99,23%.
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Los ataques a redes de información son cada vez más sofisticados y exigen una constante evolución y mejora de las técnicas de detección. Para ello, en este proyecto se ha diseñado e implementado una plataforma cooperativa para la detección de intrusiones basada en red. En primer lugar, se ha realizado un estudio teórico previo del marco tecnológico relacionado con este ámbito, en el que se describe y caracteriza el software que se utiliza para realizar ataques a sistemas (malware) así como los métodos que se utilizan para llegar a transmitir ese software (vectores de ataque). En el documento también se describen los llamados APT, que son ataques dirigidos con una gran inversión económica y temporal. Estos pueden englobar todos los malware y vectores de ataque existentes. Para poder evitar estos ataques, se estudiarán los sistemas de detección y prevención de intrusiones, describiendo brevemente los algoritmos que se tienden a utilizar en la actualidad. En segundo lugar, se ha planteado y desarrollado una plataforma en red dedicada al análisis de paquetes y conexiones para detectar posibles intrusiones. Este sistema está orientado a sistemas SCADA (Supervisory Control And Data Adquisition) aunque funciona sobre cualquier red IPv4/IPv6, para ello se definirá previamente lo que es un sistema SCADA, así como sus partes principales. Para implementar el sistema se han utilizado dispositivos de bajo consumo llamados Raspberry PI, estos se ubican entre la red y el equipo final que se quiera analizar. En ellos se ejecutan 2 aplicaciones desarrolladas de tipo cliente-servidor (la Raspberry central ejecutará la aplicación servidora y las esclavas la aplicación cliente) que funcionan de forma cooperativa utilizando la tecnología distribuida de Hadoop, la cual se explica previamente. Mediante esta tecnología se consigue desarrollar un sistema completamente escalable. La aplicación servidora muestra una interfaz gráfica que permite administrar la plataforma de análisis de forma centralizada, pudiendo ver así las alarmas de cada dispositivo y calificando cada paquete según su peligrosidad. El algoritmo desarrollado en la aplicación calcula el ratio de paquetes/tiempo que entran/salen del equipo final, procesando los paquetes y analizándolos teniendo en cuenta la información de señalización, creando diferentes bases de datos que irán mejorando la robustez del sistema, reduciendo así la posibilidad de ataques externos. Para concluir, el proyecto inicial incluía el procesamiento en la nube de la aplicación principal, pudiendo administrar así varias infraestructuras concurrentemente, aunque debido al trabajo extra necesario se ha dejado preparado el sistema para poder implementar esta funcionalidad. En el caso experimental actual el procesamiento de la aplicación servidora se realiza en la Raspberry principal, creando un sistema escalable, rápido y tolerante a fallos. ABSTRACT. The attacks to networks of information are increasingly sophisticated and demand a constant evolution and improvement of the technologies of detection. For this project it is developed and implemented a cooperative platform for detect intrusions based on networking. First, there has been a previous theoretical study of technological framework related to this area, which describes the software used for attacks on systems (malware) as well as the methods used in order to transmit this software (attack vectors). In this document it is described the APT, which are attacks directed with a big economic and time inversion. These can contain all existing malware and attack vectors. To prevent these attacks, intrusion detection systems and prevention intrusion systems will be discussed, describing previously the algorithms tend to use today. Secondly, a platform for analyzing network packets has been proposed and developed to detect possible intrusions in SCADA (Supervisory Control And Data Adquisition) systems. This platform is designed for SCADA systems (Supervisory Control And Data Acquisition) but works on any IPv4 / IPv6 network. Previously, it is defined what a SCADA system is and the main parts of it. To implement it, we used low-power devices called Raspberry PI, these are located between the network and the final device to analyze it. In these Raspberry run two applications client-server developed (the central Raspberry runs the server application and the slaves the client application) that work cooperatively using Hadoop distributed technology, which is previously explained. Using this technology is achieved develop a fully scalable system. The server application displays a graphical interface to manage analytics platform centrally, thereby we can see each device alarms and qualifying each packet by dangerousness. The algorithm developed in the application calculates the ratio of packets/time entering/leaving the terminal device, processing the packets and analyzing the signaling information of each packet, reating different databases that will improve the system, thereby reducing the possibility of external attacks. In conclusion, the initial project included cloud computing of the main application, being able to manage multiple concurrent infrastructure, but due to the extra work required has been made ready the system to implement this funcionality. In the current test case the server application processing is made on the main Raspberry, creating a scalable, fast and fault-tolerant system.
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Aplicativos móveis de celulares que coletam dados pessoais estão cada vez mais presentes na rotina do cidadão comum. Associado a estas aplicações, há polêmicas sobre riscos de segurança e de invasão de privacidade, que podem se tornar entraves para aceitação destes sistemas por parte dos usuários. Por outro lado, discute-se o Paradoxo da Privacidade, em que os consumidores revelam mais informações pessoais voluntariamente, apesar de declarar que reconhecem os riscos. Há pouco consenso, nas pesquisas acadêmicas, sobre os motivos deste paradoxo ou mesmo se este fenômeno realmente existe. O objetivo desta pesquisa é analisar como a coleta de informações sensíveis influencia a escolha de aplicativos móveis. A metodologia é o estudo de aplicativos disponíveis em lojas virtuais para celulares através de técnicas qualitativas e quantitativas. Os resultados indicam que os produtos mais populares da loja são aqueles que coletam mais dados pessoais. Porém, em uma análise minuciosa, observa-se que aqueles mais buscados também pertencem a empresas de boa reputação e possuem mais funcionalidades, que exigem maior acesso aos dados privativos do celular. Na survey realizada em seguida, nota-se que os consumidores reduzem o uso dos aplicativos quando consideram que o produto coleta dados excessivamente, mas a estratégia para proteger essas informações pode variar. No grupo dos usuários que usam aplicativos que coletam dados excessivamente, conclui-se que o motivo primordial para compartilhar informações pessoais são as funcionalidades. Além disso, esta pesquisa confirma que comparar os dados solicitados pelos aplicativos com a expectativa inicial do consumidor é um constructo complementar para avaliar preocupações com privacidade, ao invés de simplesmente analisar a quantidade de informações coletadas. O processo desta pesquisa também ilustrou que, dependendo do método utilizado para análise, é possível chegar a resultados opostos sobre a ocorrência ou não do paradoxo. Isso pode dar indícios sobre os motivos da falta de consenso sobre o assunto
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To provide more efficient and flexible alternatives for the applications of secret sharing schemes, this paper describes a threshold sharing scheme based on exponentiation of matrices in Galois fields. A significant characteristic of the proposed scheme is that each participant has to keep only one master secret share which can be used to reconstruct different group secrets according to the number of threshold values.
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Urban Mass Transportation Administration, Washington, D.C.
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Item 247.
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Includes bibliographical references (p. 17-19).
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"June 12, 2006."
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Secrecy is fundamental to computer security, but real systems often cannot avoid leaking some secret information. For this reason, the past decade has seen growing interest in quantitative theories of information flow that allow us to quantify the information being leaked. Within these theories, the system is modeled as an information-theoretic channel that specifies the probability of each output, given each input. Given a prior distribution on those inputs, entropy-like measures quantify the amount of information leakage caused by the channel. ^ This thesis presents new results in the theory of min-entropy leakage. First, we study the perspective of secrecy as a resource that is gradually consumed by a system. We explore this intuition through various models of min-entropy consumption. Next, we consider several composition operators that allow smaller systems to be combined into larger systems, and explore the extent to which the leakage of a combined system is constrained by the leakage of its constituents. Most significantly, we prove upper bounds on the leakage of a cascade of two channels, where the output of the first channel is used as input to the second. In addition, we show how to decompose a channel into a cascade of channels. ^ We also establish fundamental new results about the recently-proposed g-leakage family of measures. These results further highlight the significance of channel cascading. We prove that whenever channel A is composition refined by channel B, that is, whenever A is the cascade of B and R for some channel R, the leakage of A never exceeds that of B, regardless of the prior distribution or leakage measure (Shannon leakage, guessing entropy leakage, min-entropy leakage, or g-leakage). Moreover, we show that composition refinement is a partial order if we quotient away channel structure that is redundant with respect to leakage alone. These results are strengthened by the proof that composition refinement is the only way for one channel to never leak more than another with respect to g-leakage. Therefore, composition refinement robustly answers the question of when a channel is always at least as secure as another from a leakage point of view.^
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Background: Digital forensics is a rapidly expanding field, due to the continuing advances in computer technology and increases in data stage capabilities of devices. However, the tools supporting digital forensics investigations have not kept pace with this evolution, often leaving the investigator to analyse large volumes of textual data and rely heavily on their own intuition and experience. Aim: This research proposes that given the ability of information visualisation to provide an end user with an intuitive way to rapidly analyse large volumes of complex data, such approached could be applied to digital forensics datasets. Such methods will be investigated; supported by a review of literature regarding the use of such techniques in other fields. The hypothesis of this research body is that by utilising exploratory information visualisation techniques in the form of a tool to support digital forensic investigations, gains in investigative effectiveness can be realised. Method:To test the hypothesis, this research examines three different case studies which look at different forms of information visualisation and their implementation with a digital forensic dataset. Two of these case studies take the form of prototype tools developed by the researcher, and one case study utilises a tool created by a third party research group. A pilot study by the researcher is conducted on these cases, with the strengths and weaknesses of each being drawn into the next case study. The culmination of these case studies is a prototype tool which was developed to resemble a timeline visualisation of the user behaviour on a device. This tool was subjected to an experiment involving a class of university digital forensics students who were given a number of questions about a synthetic digital forensic dataset. Approximately half were given the prototype tool, named Insight, to use, and the others given a common open-source tool. The assessed metrics included: how long the participants took to complete all tasks, how accurate their answers to the tasks were, and how easy the participants found the tasks to complete. They were also asked for their feedback at multiple points throughout the task. Results:The results showed that there was a statistically significant increase in accuracy for one of the six tasks for the participants using the Insight prototype tool. Participants also found completing two of the six tasks significantly easier when using the prototype tool. There were no statistically significant different difference between the completion times of both participant groups. There were no statistically significant differences in the accuracy of participant answers for five of the six tasks. Conclusions: The results from this body of research show that there is evidence to suggest that there is the potential for gains in investigative effectiveness when information visualisation techniques are applied to a digital forensic dataset. Specifically, in some scenarios, the investigator can draw conclusions which are more accurate than those drawn when using primarily textual tools. There is also evidence so suggest that the investigators found these conclusions to be reached significantly more easily when using a tool with a visual format. None of the scenarios led to the investigators being at a significant disadvantage in terms of accuracy or usability when using the prototype visual tool over the textual tool. It is noted that this research did not show that the use of information visualisation techniques leads to any statistically significant difference in the time taken to complete a digital forensics investigation.
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El trabajo plantea un aporte al framework de ingeniería social (The Social Engineering Framework) para la evaluación del riesgo y mitigación de distintos vectores de ataque, por medio del análisis de árboles de ataque -- Adicionalmente se muestra una recopilación de estadísticas de ataques realizados a compañías de diferentes industrias relacionadas con la seguridad informática, enfocado en los ataques de ingeniería social y las consecuencias a las que se enfrentan las organizaciones -- Se acompañan las estadísticas con la descripción de ejemplos reales y sus consecuencias
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Nel TCR - Termina container Ravenna, è importante che nel momento di scarico del container sul camion non siano presenti persone nell’area. In questo elaborato si descrive la realizzazione e il funzionamento di un sistema di allarme automatico, in grado di rilevare persone ed eventualmente interrompere la procedura di scarico del container. Tale sistema si basa sulla tecnica della object segmentation tramite rimozione dello sfondo, a cui viene affiancata una classificazione e rimozione delle eventuali ombre con un metodo cromatico. Inoltre viene identificata la possibile testa di una persona e avendo a disposizione due telecamere, si mette in atto una visione binoculare per calcolarne l’altezza. Infine, viene presa in considerazione anche la dinamica del sistema, per cui la classificazione di una persona si può basare sulla grandezza, altezza e velocità dell’oggetto individuato.
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Modern computer systems are plagued with stability and security problems: applications lose data, web servers are hacked, and systems crash under heavy load. Many of these problems or anomalies arise from rare program behavior caused by attacks or errors. A substantial percentage of the web-based attacks are due to buffer overflows. Many methods have been devised to detect and prevent anomalous situations that arise from buffer overflows. The current state-of-art of anomaly detection systems is relatively primitive and mainly depend on static code checking to take care of buffer overflow attacks. For protection, Stack Guards and I-leap Guards are also used in wide varieties.This dissertation proposes an anomaly detection system, based on frequencies of system calls in the system call trace. System call traces represented as frequency sequences are profiled using sequence sets. A sequence set is identified by the starting sequence and frequencies of specific system calls. The deviations of the current input sequence from the corresponding normal profile in the frequency pattern of system calls is computed and expressed as an anomaly score. A simple Bayesian model is used for an accurate detection.Experimental results are reported which show that frequency of system calls represented using sequence sets, captures the normal behavior of programs under normal conditions of usage. This captured behavior allows the system to detect anomalies with a low rate of false positives. Data are presented which show that Bayesian Network on frequency variations responds effectively to induced buffer overflows. It can also help administrators to detect deviations in program flow introduced due to errors.
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Liver steatosis is a common disease usually associated with social and genetic factors. Early detection and quantification is important since it can evolve to cirrhosis. In this paper, a new computer-aided diagnosis (CAD) system for steatosis classification, in a local and global basis, is presented. Bayes factor is computed from objective ultrasound textural features extracted from the liver parenchyma. The goal is to develop a CAD screening tool, to help in the steatosis detection. Results showed an accuracy of 93.33%, with a sensitivity of 94.59% and specificity of 92.11%, using the Bayes classifier. The proposed CAD system is a suitable graphical display for steatosis classification.
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Magdeburg, Univ., Fak. für Informatik, Diss., 2013