Classifying spam emails using agglomerative hierarchical clustering and a topic-based approach

[EN] Spam emails are unsolicited, annoying and sometimes harmful messages which may contain malware, phishing or hoaxes. Unlike most studies that address the design of efficient anti-spam filters, we approach the spam email problem from a different and novel perspective. Focusing on the needs of cybersecurity units, we follow a topic-based approach for addressing the classification of spam email into multiple categories. We propose SPEMC-15K-E and SPEMC-15K-S, two novel datasets with approximately 15K emails each in English and Spanish, respectively, and we label them using agglomerative hierarchical clustering into 11 classes. We evaluate 16 pipelines, combining four text representation techniques -Term Frequency-Inverse Document Frequency (TF-IDF), Bag of Words, Word2Vec and BERT- and four classifiers: Support Vector Machine, Näive Bayes, Random Forest and Logistic Regression. Experimental results show that the highest performance is achieved with TF-IDF and LR for the English dataset, with a F1 score of 0.953 and an accuracy of 94.6%, and while for the Spanish dataset, TF-IDF with NB yields a F1 score of 0.945 and 98.5% accuracy. Regarding the processing time, TF-IDF with LR leads to the fastest classification, processing an English and Spanish spam email in 2ms and 2.2ms on average, respectively.S

A review of spam email detection: analysis of spammer strategies and the dataset shift problem

.Spam emails have been traditionally seen as just annoying and unsolicited emails containing advertisements, but they increasingly include scams, malware or phishing. In order to ensure the security and integrity for the users, organisations and researchers aim to develop robust filters for spam email detection. Recently, most spam filters based on machine learning algorithms published in academic journals report very high performance, but users are still reporting a rising number of frauds and attacks via spam emails. Two main challenges can be found in this field: (a) it is a very dynamic environment prone to the dataset shift problem and (b) it suffers from the presence of an adversarial figure, i.e. the spammer. Unlike classical spam email reviews, this one is particularly focused on the problems that this constantly changing environment poses. Moreover, we analyse the different spammer strategies used for contaminating the emails, and we review the state-of-the-art techniques to develop filters based on machine learning. Finally, we empirically evaluate and present the consequences of ignoring the matter of dataset shift in this practical field. Experimental results show that this shift may lead to severe degradation in the estimated generalisation performance, with error rates reaching values up to 48.81%.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Inner-Eye: Appearance-based Detection of Computer Scams

As more and more inexperienced users gain Internet access, fraudsters are attempting to take advantage of them in new ways. Instead of sophisticated exploitation techniques, simple confidence tricks can be used to create malware that is both very effective and likely to evade detection by traditional security software. Heuristics that detect complex malicious behavior are powerless against some common frauds. This work explores the use of imaging and text-matching techniques to detect typical computer scams such as pharmacy and rogue antivirus frauds. The Inner-Eye system implements the chosen approach in a scalable and efficient manner through the use of virtualization

Balancing usability and security in the business cloud authentication

Jatkuvasti suosiotaan kasvattavat pilvipalvelut luovat monia uusia mahdollisuuksia etätyöntekijöille, yhteistyökumppaneille ja hakkereille päästä käyttämään yrityksen työkaluja ja asiakastietoja. Kun pilvipalveluissa olevan tärkeän yritysdatan määrä kasvaa, myös palveluiden tietoturvavaatimukset kovenevat. Pilvipalveluiden tietoturvallisessa suunnittelussa tulee ottaa huomioon lukuisia erilaisia hyökkäysreittejä monella eri palvelun tasolla aina verkon rajapinnasta yksittäisten ohjelmistokomponenttien haavoittuvuuksiin. Yksi isoimmista hyökkäysvektoreista on myös reitti, joka on pakko jättää osittain avoimeksi palvelun varsinaisia käyttäjiä varten – autentikointi, eli käyttäjien todentaminen palveluun kirjautumisen yhteydessä. Diplomityön tavoitteena oli löytää tasapainokohta ja siihen vaikuttavat tekijät pilvipalveluiden käytettävyyden ja tietoturvan väliltä. Käyttäjän autentikoinnin tulee olla tarpeeksi tietoturvallinen, etteivät mahdolliset hyökkääjät pääsisi käsiksi järjestelmän arvokkaisiin dataan ja resursseihin. Samaan aikaan autentikoinnin tulee olla myös tarpeeksi käytettävää, jotta varsinaiset käyttäjät pääsevät palveluihinsa tehokkaasti ja ilman tarpeetonta turhautumista. Aihetta lähestytään kirjallisuuskatsauksella aihealueen keskeiseen tutkimukseen ja pilvipalveluihin sopivien autentikointimenetelmien kartoittamisella. Näiden lisäksi työssä suunniteltiin ja järjestettiin kuudelle osallistujalle käytettävyystesti, jossa mitattiin käyttäjien suhtautumista neljään erilaiseen autentikointimenetelmään ja niitä yhdistelevään monen menetelmän autentikointiin (multi-factor authentication). Samalla käyttäjiltä kartoitettiin puolistrukturoiduilla haastatteluilla erilaisia tekijöitä, jotka vaikuttavat heidän kokemaansa käytettävyyden ja tietoturvan tasapainoon. Tutkimuksessa tunnistettiin useita tapoja parantaa käytettävyyden ja tietoturvan tasapainoa yritysten pilvipalveluissa. Monen keskivahvan autentikointimenetelmän yhdistelmän havaittiin olevan käyttäjäystävällisempi kuin samaan tietoturvan tasoon yltävän yhden menetelmän vahvan autentikaation. Käyttäjien kouluttamisella ja tietoturvan tavoitteiden selkeällä kommunikaatiolla oli myös iso merkitys, etenkin epävirallisten, tietoturvaa heikentävien ”kiertoteiden” välttämisessä. Unohtuneiden käyttäjätunnusten uudelleenasettaminen on myös eräs usein liian vähälle huomiolle jäävä tekijä, jolla on iso vaikutus sekä järjestelmän käytettävyyteen että tietoturvaan.Increasing wave of cloud services is creating many new ways for remote workers, outsourcing partners and hackers to access the essential tools and business data of the cloud-enabled companies. As the amount of business critical data in the cloud services increase, so does the need for securing it. Securing a cloud service needs balanced defenses against many different attack vectors in various levels of the service, starting from the edges of the public network and continuing deep inside the individual design of the each software component of the cloud service. One of the biggest attack vectors is also the one route that has to be left open for the legitimate users to use the service – user authentication. The goal for this thesis was to find balance between making the user authentication in business cloud services secure enough and usable enough. Authentication has to be secure enough to prevent malicious attackers from gaining access to the valuable data and resources inside the service. At the same time it has still to be usable enough for the legitimate users to be able to access their cloud services without unnecessary frustration. The topic is approached through literature review of relevant research and relevant authentication methods. In addition, several (n=6) usability tests are performed in combination with half-structured interviews to evaluate the user preference in authentication method selection and the factors affecting the experienced balance of security and usability. In addition, the thesis evaluates other important factors, in addition to the authentication method itself, that are affecting the security – usability –balance of the entire authentication process. As a result the thesis presents several ways to improve the balance of usability and security in business cloud services. Multifactor authentication is observed to be more usable than equally secure single-factor authentication. Educating the users and communicating the security needs clearly helps to reduce the unsanctioned security “shortcuts” that reduce the overall security. Authentication resetting is often neglected, but really essential factor both as usability hindrance and possible attack vector

Improving Authentication for Users via Better Understanding Password Use and Abuse

Passwords are our primary form of authentication. Yet passwords are a major vulnerability for computer systems due to their predictable nature, in fact Florêncio et al., conclude that human limitations makes what is often considered to be “proper password use” impossible [52]. It is vital we improve authentication with respect to both security and usability. The aim of this research is to investigate password use and abuse in order to improve authentication for users. We investigate circulated password advice that claims to help in this security fight. We find that it is contradictory, often at odds with best practice and research findings, and can be ambiguous and taxing on users. We complete a user study investigating user and administrator perceptions of the password advice collected. We leverage knowledge of security benefits, usability and organisation costs to investigate the trade-offs that exist when security advice is enforced. To improve password systems, effective and accurate information is needed regarding the prevalence of security vulnerabilities. We develop a guessability metric which produces guessing success results that are independent of the underlying distribution of the data. We use this to prove that small password breaches can lead to major vulnerabilities to entire cohorts of other users. We also demonstrate that a tailored learning algorithm can actively learn characteristics of the passwords it is guessing, and that it can leverage this information to improve its guessing. We demonstrate that characteristics such as nationality can be derived from data and used to improve guessing, this reduces security in an online environment and potentially leaks private information about cohorts of users. Finally, we design models to quantify the effectiveness of security policies. We demonstrate the value of the NIST 2017 guidelines. We find that if an organisation is willing to bear costs on themselves, they can significantly improve usability for their end-users, and simultaneously increase their security

Exploring a New Paradigm for Evangelism in the Emerging Culture

It is my claim that evangelism has become focused on the proclamation of a message that is presumed to be an accurate expression of the biblical concept of gospel. Evangelism within the evangelical community, perceived primarily as proclamation, has become a specialized function of the church. It is too often separated not only from the normative experience of the average Christian but also from the idea of discipleship, or spiritual formation. There are possible solutions to this problem, such as more training, increased efforts at city-wide crusades, more seeker-oriented services, continuation of church planting, a stronger focus on those gifted to do evangelism or even the dismantling of traditional churches and the releasing of people into natural connections with non-Christian people. Although many different types of efforts at evangelism continue to take place, the effects appear to be minimal since researchers show that church attendance and affiliation with Christian faith is decreasing in the United States. I am further claiming that evangelism is properly understood as a multi-faceted expression of the reality of God\u27s kingdom that involves human participation in God\u27s ongoing ministry in the world and is demonstrated as an outflow of Christian spiritual formation. I will explore the practice of spiritual direction and suggest how that ancient practice provides an appropriate approach to evangelism in the emerging culture. I am proposing a book in the form of a fictional narrative in order to illustrate how the natural expression of evangelism in the form of spiritual direction might take place in the lives of people in a way that is very different from more traditional forms of evangelism. My project will address the challenges that western Christians face in evangelism in terms of both theology and practice. The story will be a narrative that is formed around the key elements of my research

Le Forum, Vol. 42 No. 2

https://digitalcommons.library.umaine.edu/francoamericain_forum/1095/thumbnail.jp

Visual Social Media and Vernacular Responses to Environmental Issues in China

This thesis investigates the role of visual social media in providing ordinary Chinese with an alternative space to articulate their opinions on environmental issues. By studying three notable environmental cases, this thesis explores how ordinary Chinese adopt visual social media practices as a response to environmental issues, and to aid in the fight for environmental justice. This thesis provides a new perspective to understand China’s visual social media practices and its networked civic engagement

Battling the Dark Arts: Combating Stock Market Manipulation in Australia – From the Early Days of Share Trading to 1990

This thesis traces the historical roots of stock market manipulation in the domestic context, from the early days of share trading to 1990—the year of the first successful prosecution for market rigging in Australia. It will consider the role that governments and stock exchanges have played in combating this insidious activity, which has plagued domestic stock markets since share trading began on the streets of gold mining towns across the Australian colonies