The advent of the Internet has generated a proliferation of online information-rich environments, which provide information consumers with an unprecedented amount of freely available information. However, the openness of these environments has also made them vulnerable to a new class of attacks called Denial of Information (DoI) attacks. Attackers launch these attacks by deliberately inserting low quality information into information-rich environments to promote that information or to deny access to high quality information. These attacks directly threaten the usefulness and dependability of online information-rich environments, and as a result, an important research question is how to automatically identify and remove this low quality information from these environments. The first contribution of this thesis research is a set of techniques for automatically recognizing and countering various forms of DoI attacks in email systems. We develop a new DoI attack based on camouflaged messages, and we show that spam producers and information consumers are entrenched in a spam arms race. To break free of this arms race, we propose two solutions. One solution involves refining the statistical learning process by associating disproportionate weights to spam and legitimate features, and the other solution leverages the existence of non-textual email features (e.g., URLs) to make the classification process more resilient against attacks. The second contribution of this thesis is a framework for collecting, analyzing, and classifying examples of DoI attacks in the World Wide Web. We propose a fully automatic Web spam collection technique and use it to create the Webb Spam Corpus -- a first-of-its-kind, large-scale, and publicly available Web spam data set. Then, we perform the first large-scale characterization of Web spam using content and HTTP session analysis. Next, we present a lightweight, predictive approach to Web spam classification that relies exclusively on HTTP session information. The final contribution of this thesis research is a collection of techniques that detect and help prevent DoI attacks within social environments. First, we provide detailed descriptions for each of these attacks. Then, we propose a novel technique for capturing examples of social spam, and we use our collected data to perform the first characterization of social spammers and their behaviors.

Thesis (doctoral)--Albert-Ludwigs-Universität Freiburg im Breisgau, 2007. / Includes bibliographical references (p. 271-284).

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-10-03T19:06:58Z No. of bitstreams: 1 ALBERTO_Tulio_2017.pdf: 2422402 bytes, checksum: 127bff2089f3d274b1abaa58c3d32578 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-10-03T19:07:11Z (GMT) No. of bitstreams: 1 ALBERTO_Tulio_2017.pdf: 2422402 bytes, checksum: 127bff2089f3d274b1abaa58c3d32578 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-10-03T19:07:27Z (GMT) No. of bitstreams: 1 ALBERTO_Tulio_2017.pdf: 2422402 bytes, checksum: 127bff2089f3d274b1abaa58c3d32578 (MD5) / Made available in DSpace on 2017-10-03T19:07:37Z (GMT). No. of bitstreams: 1 ALBERTO_Tulio_2017.pdf: 2422402 bytes, checksum: 127bff2089f3d274b1abaa58c3d32578 (MD5) Previous issue date: 2017-02-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / YouTube has become an important video sharing platform. Several users regularly produce video content and make this task their main livelihood. However, such success is also drawing the attention of malicious users propagating undesired comments and videos, looking for self-promotion or disseminating malicious links which may have malwares and viruses. Since YouTube offers limited tools for blocking spam, the volume of such messages is shockingly increasing and harming users and channels owners. In addition to the problem being naturally online, comment spam filtering on YouTube is different than the traditional email spam filtering, since the messages are very short and often rife with spelling errors, slangs, symbols and abbreviations. This manuscript presents a performance evaluation of traditional online classification methods, aided by lexical normalization and semantic indexing techniques when applied to automatic filter YouTube comment spam. It was also evaluated the performance of MDLText, a promising text classification method based on the minimum description length principle. The statistical analysis of the results indicates that MDLText, Passive-Aggressive, Naïve Bayes, MDL and Online Gradient Descent obtained statistically equivalent performances. The results also indicate that the lexical normalization and semantic indexing techniques are effective to be applied to the problem. Based on the results, it is proposed and designed TubeSpam, an online tool to automatic filter undesired comments posted on YouTube. / O YouTube tem se tornado uma importante plataforma de compartilhamento de vídeos. Muitos usuários produzem regularmente conteúdo em vídeo e fazem desta tarefa seu principal meio de vida. Contudo, esse sucesso também vem despertando a atenção de usuários mal-intencionados, que propagam comentários e vídeos indesejados para se autopromoverem ou para disseminar links maliciosos que podem conter vírus e malwares. Visto que o YouTube atualmente oferece recursos limitados para bloquear spam, o volume dessas mensagens está impactando muitos usuários e proprietários de canais. Além da característica inerentemente online do problema, filtrar spam nos comentários do YouTube é uma tarefa que difere-se da tradicional filtragem de spam em emails, pois as mensagens costumam ser muito mais curtas e repletas de erros de digitação, gírias, símbolos e abreviações que podem dificultar a tarefa de classificação. Assim, nesta dissertação é apresentada a avaliação de desempenho obtido por métodos tradicionais de classificação online auxiliados por técnicas de normalização léxica e indexação semântica, quando aplicados na filtragem automática de comentários indesejados postados no YouTube. Foi avaliado também o desempenho do MDLText, um promissor método de classificação de texto baseado no princípio da descrição mais simples. A análise estatística dos resultados indica que os métodos MDLText, Passivo-Agressivo, Naïve Bayes, MDL e Gradiente Descendente Online obtiveram desempenhos equivalentes. Além disso, os resultados também indicam que o uso de técnicas de normalização léxica e indexação semântica são eficazes para atenuar os problemas de representação de texto e, consequentemente, aumentar o poder de predição dos métodos de classificação. Baseado nos resultados dos experimentos, foi proposto e desenvolvido o TubeSpam, uma ferramenta online para filtrar automaticamente comentários indesejados postados no YouTube.

The present interview revolves around electronic mal of employees as a work tool and his relationship with the right of privacy and secrecy of telecommunications. Thus, it attempts to figure out the nature of electronic mail and other technologies as work tools, making difference from this same technologies in a personal context. / La presente entrevista gira en torno al correo electrónico del empleado como herramienta de trabajo y su interrelación con el derecho de la intimidad y el secreto de las telecomunicaciones. Así, se intenta descifrar cuál es la naturaleza del correo electrónico y otras tecnologías como herramientas de trabajo, a diferencia de las tecnologías de uso personal.

This study examines the conditions for successful online mentoring in order to develop writing skills in English in a workplace setting. Chapter 1 gives the background and context of the study. Problems to be addressed in the study and the aims, objectives, hypotheses and their rationale are presented. This is followed by testing procedures, research design, sources of data and research procedures. In Chapter 2, the literature review supports the hypotheses on the need for collaboration in materials development and delivery, mentoring relationships, motivation and computer and Internet efficacy. Chapter 3 presents the findings from the case study bringing into focus problems that would jeopardise a mentoring programme if training providers do not pay attention to the hypotheses. The findings are collated and the hypotheses are confirmed. Conditions for successful online mentoring are spelt out in Chapter 4. The study concludes that online mentoring works once the conditions are properly followed. / English Studies / M.A. (TESOL)

Internal marketing and internal communication are essential tools to align em-ployees’ mindsets with the necessary tasks which bring about employee satis-faction and organisational prosperity. Electronic newsletters serve as an internal marketing communication medium which can convey the necessary information to employees regarding the organisation’s goals and objectives. They also act as a medium to build relationships with employees and encourage improved service delivery and customer-oriented employee mindsets. Employees’ willingness to make use of electronic newsletters for the purpose of disseminating organisational information is an indication of employees’ acceptance of the organisational information and use thereof in performing organisational tasks successfully as the organisation intends. The purpose of the current study was to determine employees’ acceptance of electronic newsletters, as an internal marketing communication medium, in order to disseminate organisational information which contributes to the attainment of organisational goals, objectives and success. An empirical study was conducted to determine employees’ acceptance of elec-tronic newsletters by means of an adapted technology acceptance model, self-administered, e-mail survey disseminated to employees of a higher education institution. The study followed a quantitative research approach, utilising re-gression in the analysis of the data. Based on the research results, employees do accept the electronic newsletter for the dissemination of organisational information, albeit with suggestions on how it can be better utilised in future. / Business Management / M. Com (Business Management)

Made available in DSpace on 2014-12-17T14:52:57Z (GMT). No. of bitstreams: 1 SayonaraMC.pdf: 1577994 bytes, checksum: 8c1104c0f89bd94527f5d3cd7e2f3b06 (MD5) Previous issue date: 2006-05-19 / The electronic mail service is one of the most Internet services that grow in the corporate environment. This evolution is bringing several problems for the organizations, especially to information that circulates inside of the corporate net. The lack of correct orientation to the people, about the usage and the security importance of these resources, is leaving breaches and causing misusage and overuse of service, for example. In recent literature, it starts to coming out several ideas, which has helped to rganizations how to plain and how to implement the information security system to the electronic mail in computer environment. However, these ideas are still not placed in practice in many companies, public or private. This dissertation tries to demonstrate the results of a research that has like goal, identify the importance that user training has over the information security policy, through a case study inside of private superior education institute in this state. Besides, this work had by basic orientation the ISO/IEC 17799, which talk about People Security. This study was developed over a proposed model to this research, which looked for offer conditions to guide the institution studied, how to plan better a information security policy to the electronic mail. Also, this research has an exploratory and descreptive nature and your type, qualitative. Firstly, it was applied na questionary to the information technology manager, as better way to get some general data and to deepen the contact which still then, it was being kept through e-mail. Thereupon this first contact, eleven interviews were done with the same manager, beside one interview with twenty-four users, among employees e students. After that to collect and transcript the interviews, were review with the manager all informations given, to correct any mistakes and to update that informations, to then, start the data analyze. The research suggests that the institution has a pro attitude about the information security policy and the electronic mail usage. However, it was clear that answers have their perception about information security under a very inexperient way, derived of a planning lack in relation to training program capable to solve the problem / O servi?o de correio eletr?nico ? um dos servi?os da Internet que mais cresce no ambiente corporativo. Essa evolu??o vem trazendo v?rios problemas para as organiza??es no que tange principalmente aos tipos de informa??es que circulam dentro da rede corporativa. A falta de orienta??o adequada, ?s pessoas, sobre a import?ncia do uso seguro destes recursos, vem deixando brechas e ocasionando tanto o mau uso quanto o abuso do servi?o, entre outros. Na literatura mais recente come?am a surgir conjuntos de id?ias consistentes, as quais t?m auxiliado as organiza??es em como planejar e implantar um sistema de seguran?a da informa??o para o correio eletr?nico em ambientes computacionais. Entretanto, tais id?ias ainda n?o foram devidamente postas em pr?tica em muitas empresas, p?blicas ou privadas. Esta disserta??o procura demonstrar os resultados de uma pesquisa que teve por objetivo identificar a import?ncia que o treinamento do usu?rio tem sobre a pol?tica de seguran?a das informa??es nas empresas, atrav?s de um estudo de caso feito em uma institui??o de ensino superior do Estado. Adicionalmente, o trabalho teve por orienta??o b?sica a diretriz da ISO/IEC 17799 (Tecnologia da informa??o C?digo de pr?tica para a gest?o da seguran?a da informa??o) a qual possui um t?pico dedicado ? Seguran?a de Pessoas. O estudo foi desenvolvido em cima de um modelo proposto para esta pesquisa, o qual procura oferecer condi??es de orienta??o para a institui??o estudada melhor planejar uma pol?tica de seguran?a da informa??o para o correio eletr?nico. Esta pesquisa teve natureza explorat?ria e descritiva e sua abordagem, qualitativa. Inicialmente, foi aplicado um question?rio junto a gerente de inform?tica da institui??o, como forma de melhor obter alguns dados gerais e tamb?m para aprofundar o contato que at? ent?o, vinha sendo mantido por e-mail. Logo ap?s este contato inicial, foram realizadas onze entrevistas com a mesma gerente, al?m de uma entrevista com vinte e quatro usu?rios, dispostos entre funcion?rios e alunos. Ap?s a fase de coleta e transcri??es das entrevistas, foram ainda revisadas com a gerente todas as informa??es fornecidas, a fim de corrigir quaisquer distor??es, bem como atualizar tais informa??es, para ent?o se come?ar a an?lise dos dados propriamente dita. A pesquisa sugere que a institui??o possui uma atitude pr?-ativa em rela??o ? seguran?a de suas informa??es e ? utiliza??o do correio eletr?nico. Entretanto, ficou evidenciado que os respondentes t?m sua percep??o sobre seguran?a da informa??o sob uma forma bastante inexperiente, derivada da falta de planejamento de uma pol?tica de treinamento capaz de sanar tal problema

Networks of maliciously compromised computers, known as botnets, consisting of thousands of hosts have emerged as a serious threat to Internet security in recent years. These compromised systems, under the control of an operator are used to steal data, distribute malware and spam, launch phishing attacks and in Distributed Denial-of-Service (DDoS) attacks. The operators of these botnets use Command and Control (C2) servers to communicate with the members of the botnet and send commands. The communications channels between the C2 nodes and endpoints have employed numerous detection avoidance mechanisms to prevent the shutdown of the C2 servers. Two prevalent detection avoidance techniques used by current botnets are algorithmically generated domain names and DNS Fast-Flux. The use of these mechanisms can however be observed and used to create distinct signatures that in turn can be used to detect DNS domains being used for C2 operation. This report details research conducted into the implementation of three classes of classification techniques that exploit these signatures in order to accurately detect botnet traffic. The techniques described make use of the traffic from DNS query responses created when members of a botnet try to contact the C2 servers. Traffic observation and categorisation is passive from the perspective of the communicating nodes. The first set of classifiers explored employ frequency analysis to detect the algorithmically generated domain names used by botnets. These were found to have a high degree of accuracy with a low false positive rate. The characteristics of Fast-Flux domains are used in the second set of classifiers. It is shown that using these characteristics Fast-Flux domains can be accurately identified and differentiated from legitimate domains (such as Content Distribution Networks exhibit similar behaviour). The final set of classifiers use spatial autocorrelation to detect Fast-Flux domains based on the geographic distribution of the botnet C2 servers to which the detected domains resolve. It is shown that botnet C2 servers can be detected solely based on their geographic location. This technique is shown to clearly distinguish between malicious and legitimate domains. The implemented classifiers are lightweight and use existing network traffic to detect botnets and thus do not require major architectural changes to the network. The performance impact of implementing classification of DNS traffic is examined and it is shown that the performance impact is at an acceptable level.

The project is a web e-mail application to provide a web page interface for all CSCI faculty, staff and students to handle their e-mails. The application is written by JSP, Java Servlets, JavaScript and custom JSP tag libraries. Regular e-mail capabilities have been enhanced by the feature of allowing users to store and manage messages by day (store to daily folders, view in daily folders, append notes for that day).

The main purpose of this master's thesis is to create electronic mail room of The BUT. First of all I described problems concerning a digital signature, its use and safety, and as well as sphere of qualified certificates and method of their issuing by certification authority. The next part of the thesis deals with systems enabling electronic submission (so-called "Electronic Mail Room"). I have focused on available applications providing electronic submission service to civil offices, and subsequently analyzed functions that individual applications offer to the Mail Room clients as well as to authority staff. On the basis of gained knowledge and according CVIS requirements I created project of electronic submission for needs of the Brno University of Technology. Result of this thesis is the application of electronic mail room, implemented in BUT portal.