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dc.contributor.advisorDel Ser, Javier
dc.contributor.advisorSalcedo-Sanz, Sancho
dc.contributor.authorVillar-Rodriguez, Esther
dc.date.accessioned2016-04-08T09:41:57Z
dc.date.available2016-04-08T09:41:57Z
dc.date.issued2015-12-11
dc.identifier.urihttp://hdl.handle.net/11556/182
dc.description.abstractAccording to the report published by the online protection firm Iovation in 2012, cyber fraud ranged from 1 percent of the Internet transactions in North America Africa to a 7 percent in Africa, most of them involving credit card fraud, identity theft, and account takeover or h¼acking attempts. This kind of crime is still growing due to the advantages offered by a non face-to-face channel where a increasing number of unsuspecting victims divulges sensitive information. Interpol classifies these illegal activities into 3 types: • Attacks against computer hardware and software. • Financial crimes and corruption. • Abuse, in the form of grooming or “sexploitation”. Most research efforts have been focused on the target of the crime developing different strategies depending on the casuistic. Thus, for the well-known phising, stored blacklist or crime signals through the text are employed eventually designing adhoc detectors hardly conveyed to other scenarios even if the background is widely shared. Identity theft or masquerading can be described as a criminal activity oriented towards the misuse of those stolen credentials to obtain goods or services by deception. On March 4, 2005, a million of personal and sensitive information such as credit card and social security numbers was collected by White Hat hackers at Seattle University who just surfed the Web for less than 60 minutes by means of the Google search engine. As a consequence they proved the vulnerability and lack of protection with a mere group of sophisticated search terms typed in the engine whose large data warehouse still allowed showing company or government websites data temporarily cached. As aforementioned, platforms to connect distant people in which the interaction is undirected pose a forcible entry for unauthorized thirds who impersonate the licit user in a attempt to go unnoticed with some malicious, not necessarily economic, interests. In fact, the last point in the list above regarding abuses has become a major and a terrible risk along with the bullying being both by means of threats, harassment or even self-incrimination likely to drive someone to suicide, depression or helplessness. California Penal Code Section 528.5 states: “Notwithstanding any other provision of law, any person who knowingly and without consent credibly impersonates another actual person through or on an Internet Web site or by other electronic means for purposes of harming, intimidating, threatening, or defrauding another person is guilty of a public offense punishable pursuant to subdivision [...]”. IV Therefore, impersonation consists of any criminal activity in which someone assumes a false identity and acts as his or her assumed character with intent to get a pecuniary benefit or cause some harm. User profiling, in turn, is the process of harvesting user information in order to construct a rich template with all the advantageous attributes in the field at hand and with specific purposes. User profiling is often employed as a mechanism for recommendation of items or useful information which has not yet considered by the client. Nevertheless, deriving user tendency or preferences can be also exploited to define the inherent behavior and address the problem of impersonation by detecting outliers or strange deviations prone to entail a potential attack. This dissertation is meant to elaborate on impersonation attacks from a profiling perspective, eventually developing a 2-stage environment which consequently embraces 2 levels of privacy intrusion, thus providing the following contributions: • The inference of behavioral patterns from the connection time traces aiming at avoiding the usurpation of more confidential information. When compared to previous approaches, this procedure abstains from impinging on the user privacy by taking over the messages content, since it only relies on time statistics of the user sessions rather than on their content. • The application and subsequent discussion of two selected algorithms for the previous point resolution: – A commonly employed supervised algorithm executed as a binary classifier which thereafter has forced us to figure out a method to deal with the absence of labeled instances representing an identity theft. – And a meta-heuristic algorithm in the search for the most convenient parameters to array the instances within a high dimensional space into properly delimited clusters so as to finally apply an unsupervised clustering algorithm. • The analysis of message content encroaching on more private information but easing the user identification by mining discriminative features by Natural Language Processing (NLP) techniques. As a consequence, the development of a new feature extraction algorithm based on linguistic theories motivated by the massive quantity of features often gathered when it comes to texts. In summary, this dissertation means to go beyond typical, ad-hoc approaches adopted by previous identity theft and authorship attribution research. Specifically it proposes tailored solutions to this particular and extensively studied paradigm with the aim at introducing a generic approach from a profiling view, not tightly bound to a unique application field. In addition technical contributions have been made in the course of the solution formulation intending to optimize familiar methods for a better versatility towards the problem at hand. In summary: this Thesis establishes an encouraging research basis towards unveiling subtle impersonation attacks in Social Networks by means of intelligent learning techniques.en
dc.language.isoengen
dc.publisherUniversidad de Alcaláen
dc.rightsAttribution-NonCommercial-ShareAlike 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/4.0/*
dc.titleAdvanced Machine Learning Techniques and Meta-Heuristic Optimization for the Detection of Masquerading Attacks in Social Networksen
dc.typedoctoralThesisen
dc.rights.accessRightsopenAccessen
dc.subject.keywordsSocial Networksen
dc.subject.keywordsSNsen
dc.subject.keywordsMasquerading attacksen
dc.subject.keywordsMeta-Heuristicsen
dc.subject.keywordsOptimizationen
dc.subject.keywordsNatural Languaje Processingen
dc.subject.keywordsNLPen


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