Visualising network security attacks with multiple 3D visualisation and false alert classification

Increasing numbers of alerts produced by network intrusion detection systems (NIDS) have burdened the job of security analysts especially in identifying and responding to them. The tasks of exploring and analysing large quantities of communication network security data are also difficult. This thesis studied the application of visualisation in combination with alerts classifier to make the exploring and understanding of network security alerts data faster and easier. The prototype software, NSAViz, has been developed to visualise and to provide an intuitive presentation of the network security alerts data using interactive 3D visuals with an integration of a false alert classifier. The needs analysis of this prototype was based on the suggested needs of network security analyst's tasks as seen in the literatures. The prototype software incorporates various projections of the alert data in 3D displays. The overview was plotted in a 3D plot named as "time series 3D AlertGraph" which was an extension of the 2D histographs into 3D. The 3D AlertGraph was effectively summarised the alerts data and gave the overview of the network security status. Filtering, drill-down and playback of the alerts at variable speed were incorporated to strengthen the analysis. Real-time visual observation was also included. To identify true alerts from all alerts represents the main task of the network security analyst. This prototype software was integrated with a false alert classifier using a classification tree based on C4.5 classification algorithm to classify the alerts into true and false. Users can add new samples and edit the existing classifier training sample. The classifier performance was measured using k-fold cross-validation technique. The results showed the classifier was able to remove noise in the visualisation, thus making the pattern of the true alerts to emerge. It also highlighted the true alerts in the visualisation. Finally, a user evaluation was conducted to find the usability problems in the tool and to measure its effectiveness. The feed backs showed the tools had successfully helped the task of the security analyst and increased the security awareness in their supervised network. From this research, the task of exploring and analysing a large amount of network security data becomes easier and the true attacks can be identified using the prototype visualisation tools. Visualisation techniques and false alert classification are helpful in exploring and analysing network security data.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Mining intrusion detection alert logs to minimise false positives & gain attack insight

Utilising Intrusion Detection System (IDS) logs in security event analysis is crucial in the process of assessing, measuring and understanding the security state of a computer network, often defined by its current exposure and resilience to network attacks. Thus, the study of understanding network attacks through event analysis is a fast growing emerging area. In comparison to its first appearance a decade ago, the complexities involved in achieving effective security event analysis have significantly increased. With such increased complexities, advances in security event analytical techniques are required in order to maintain timely mitigation and prediction of network attacks. This thesis focusses on improving the quality of analysing network event logs, particularly intrusion detection logs by exploring alternative analytical methods which overcome some of the complexities involved in security event analysis. This thesis provides four key contributions. Firstly, we explore how the quality of intrusion alert logs can be improved by eliminating the large volume of false positive alerts contained in intrusion detection logs. We investigate probabilistic alert correlation, an alternative to traditional rule based correlation approaches. We hypothesise that probabilistic alert correlation aids in discovering and learning the evolving dependencies between alerts, further revealing attack structures and information which can be vital in eliminating false positives. Our findings showed that the results support our defined hypothesis, aligning consistently with existing literature. In addition, evaluating the model using recent attack datasets (in comparison to outdated datasets used in many research studies) allowed the discovery of a new set of issues relevant to modern security event log analysis which have only been introduced and addressed in few research studies. Secondly, we propose a set of novel prioritisation metrics for the filtering of false positive intrusion alerts using knowledge gained during alert correlation. A combination of heuristic, temporal and anomaly detection measures are used to define metrics which capture characteristics identifiable in common attacks including denial-of-service attacks and worm propagations. The most relevant of the novel metrics, Outmet is based on the well known Local Outlier Factor algorithm. Our findings showed that with a slight trade-off of sensitivity (i.e. true positives performance), outmet reduces false positives significantly. In comparison to prior state-of-the-art, our findings show that it performs more efficiently given a variation of attack scenarios. Thirdly, we extend a well known real-time clustering algorithm, CluStream in order to support the categorisation of attack patterns represented as graph like structures. Our motive behind attack pattern categorisation is to provide automated methods for capturing consistent behavioural patterns across a given class of attacks. To our knowledge, this is a novel approach to intrusion alert analysis. The extension of CluStream resulted is a novel light weight real-time clustering algorithm for graph structures. Our findings are new and complement existing literature. We discovered that in certain case studies, repetitive attack behaviour could be mined. Such a discovery could facilitate the prediction of future attacks. Finally, we acknowledge that due to the intelligence and stealth involved in modern network attacks, automated analytical approaches alone may not suffice in making sense of intrusion detection logs. Thus, we explore visualisation and interactive methods for effective visual analysis which if combined with the automated approaches proposed, would improve the overall results of the analysis. The result of this is a visual analytic framework, integrated and tested in a commercial Cyber Security Event Analysis Software System distributed by British Telecom

A Survey, Taxonomy, and Analysis of Network Security Visualization Techniques

Network security visualization is a relatively new field and is quickly gaining momentum. Network security visualization allows the display and projection of the network or system data, in hope to efficiently monitor and protect the system from any intrusions or possible attacks. Intrusions and attacks are constantly continuing to increase in number, size, and complexity. Textually reading through log files or other textual sources is currently insufficient to secure a network or system. Using graphical visualization, security information is presented visually, and not only by text. Without network security visualization, reading through log files or other textual sources is an endless and aggravating task for network security analysts. Visualization provides a method of displaying large volume of information in a relatively small space. It also makes patterns easier to detect, recognize, and analyze. This can help security experts to detect problems that may otherwise be missed in reading text based log files. Network security visualization has become an active research field in the past six years and a large number of visualization techniques have been proposed. A comprehensive analysis of the existing techniques is needed to help network security designers make informed decisions about the appropriate visualization techniques under various circumstances. Moreover, a taxonomy of the existing visualization techniques is needed to classify the existing network security visualization techniques and present a high level overview of the field. In this thesis, the author surveyed the field of network security visualization. Specifically, the author analyzed the network security visualization techniques from the perspective of data model, visual primitives, security analysis tasks, user interaction, and other design issues. Various statistics were generated from the literatures. Based on this analysis, the author has attempted to generate useful guidelines and principles for designing effective network security visualization techniques. The author also proposed a taxonomy for the security visualization techniques. To the author’s knowledge, this is the first attempt to generate a taxonomy for network security visualization. Finally, the author evaluated the existing network security visualization techniques and discussed their characteristics and limitations. For future research, the author also discussed some open research problems in this field. This research is a step towards a thorough analysis of the problem space and the solution space in network security visualization

Visualisation d'événements de sécurité centrée autour de l'utilisateur

Managing the vast quantities of data generated in the context of information system security becomes more difficult every day. Visualisation tools are a solution to help face this challenge. They represent large quantities of data in a synthetic and often aesthetic way to help understand and manipulate them. In this document, we first present a classification of security visualisation tools according to each of their objectives. These can be one of three: monitoring (following events in real time to identify attacks as early as possible), analysis (the exploration and manipulation a posteriori of a an important quantity of data to discover important events) or reporting (representation a posteriori of known information in a clear and synthetic fashion to help communication and transmission). We then present ELVis, a tool capable of representing security events from various sources coherently. ELVis automatically proposes appropriate representations in function of the type of information (time, IP address, port, data volume, etc.). In addition, ELVis can be extended to accept new sources of data. Lastly, we present CORGI, an successor to ELVIS which allows the simultaneous manipulation of multiple sources of data to correlate them. With the help of CORGI, it is possible to filter security events from a datasource by multiple criteria, which facilitates following events on the currently analysed information systems.Il est aujourd'hui de plus en plus difficile de gérer les énormes quantités de données générées dans le cadre de la sécurité des systèmes. Les outils de visualisation sont une piste pour faire face à ce défi. Ils représentent de manière synthétique et souvent esthétique de grandes quantités de données et d'événements de sécurité pour en faciliter la compréhension et la manipulation. Dans ce document, nous présentons tout d'abord une classification des outils de visualisation pour la sécurité en fonction de leurs objectifs respectifs. Ceux-ci peuvent être de trois ordres : monitoring (c'est à dire suivi en temps réel des événements pour identifier au plus tôt les attaques alors qu'elles se déroulent), exploration (parcours et manipulation a posteriori d'une quantité importante de données pour découvrir les événements importants) ou reporting (représentation a posteriori d'informations déjà connues de manière claire et synthétique pour en faciliter la communication et la transmission). Ensuite, nous présentons ELVis, un outil capable de représenter de manière cohérente des évènements de sécurité issus de sources variées. ELVis propose automatiquement des représentations appropriées en fonction du type des données (temps, adresse IP, port, volume de données, etc.). De plus, ELVis peut être étendu pour accepter de nouvelles sources de données. Enfin, nous présentons CORGI, une extension d'ELVIs permettant de manipuler simultanément plusieurs sources de données pour les corréler. A l'aide de CORGI, il est possible de filtrer les évènements de sécurité provenant d'une source de données en fonction de critères résultant de l'analyse des évènements de sécurité d'une autre source de données, facilitant ainsi le suivi des évènements sur le système d'information en cours d'analyse

Performance Metrics for Network Intrusion Systems

Intrusion systems have been the subject of considerable research during the past 33 years, since the original work of Anderson. Much has been published attempting to improve their performance using advanced data processing techniques including neural nets, statistical pattern recognition and genetic algorithms. Whilst some significant improvements have been achieved they are often the result of assumptions that are difficult to justify and comparing performance between different research groups is difficult. The thesis develops a new approach to defining performance focussed on comparing intrusion systems and technologies. A new taxonomy is proposed in which the type of output and the data scale over which an intrusion system operates is used for classification. The inconsistencies and inadequacies of existing definitions of detection are examined and five new intrusion levels are proposed from analogy with other detection-based technologies. These levels are known as detection, recognition, identification, confirmation and prosecution, each representing an increase in the information output from, and functionality of, the intrusion system. These levels are contrasted over four physical data scales, from application/host through to enterprise networks, introducing and developing the concept of a footprint as a pictorial representation of the scope of an intrusion system. An intrusion is now defined as “an activity that leads to the violation of the security policy of a computer system”. Five different intrusion technologies are illustrated using the footprint with current challenges also shown to stimulate further research. Integrity in the presence of mixed trust data streams at the highest intrusion level is identified as particularly challenging. Two metrics new to intrusion systems are defined to quantify performance and further aid comparison. Sensitivity is introduced to define basic detectability of an attack in terms of a single parameter, rather than the usual four currently in use. Selectivity is used to describe the ability of an intrusion system to discriminate between attack types. These metrics are quantified experimentally for network intrusion using the DARPA 1999 dataset and SNORT. Only nine of the 58 attack types present were detected with sensitivities in excess of 12dB indicating that detection performance of the attack types present in this dataset remains a challenge. The measured selectivity was also poor indicting that only three of the attack types could be confidently distinguished. The highest value of selectivity was 3.52, significantly lower than the theoretical limit of 5.83 for the evaluated system. Options for improving selectivity and sensitivity through additional measurements are examined.Stochastic Systems Lt

Decision Support Elements and Enabling Techniques to Achieve a Cyber Defence Situational Awareness Capability

[ES] La presente tesis doctoral realiza un análisis en detalle de los elementos de decisión necesarios para mejorar la comprensión de la situación en ciberdefensa con especial énfasis en la percepción y comprensión del analista de un centro de operaciones de ciberseguridad (SOC). Se proponen dos arquitecturas diferentes basadas en el análisis forense de flujos de datos (NF3). La primera arquitectura emplea técnicas de Ensemble Machine Learning mientras que la segunda es una variante de Machine Learning de mayor complejidad algorítmica (lambda-NF3) que ofrece un marco de defensa de mayor robustez frente a ataques adversarios. Ambas propuestas buscan automatizar de forma efectiva la detección de malware y su posterior gestión de incidentes mostrando unos resultados satisfactorios en aproximar lo que se ha denominado un SOC de próxima generación y de computación cognitiva (NGC2SOC). La supervisión y monitorización de eventos para la protección de las redes informáticas de una organización debe ir acompañada de técnicas de visualización. En este caso, la tesis aborda la generación de representaciones tridimensionales basadas en métricas orientadas a la misión y procedimientos que usan un sistema experto basado en lógica difusa. Precisamente, el estado del arte muestra serias deficiencias a la hora de implementar soluciones de ciberdefensa que reflejen la relevancia de la misión, los recursos y cometidos de una organización para una decisión mejor informada. El trabajo de investigación proporciona finalmente dos áreas claves para mejorar la toma de decisiones en ciberdefensa: un marco sólido y completo de verificación y validación para evaluar parámetros de soluciones y la elaboración de un conjunto de datos sintéticos que referencian unívocamente las fases de un ciberataque con los estándares Cyber Kill Chain y MITRE ATT & CK.[CA] La present tesi doctoral realitza una anàlisi detalladament dels elements de decisió necessaris per a millorar la comprensió de la situació en ciberdefensa amb especial èmfasi en la percepció i comprensió de l'analista d'un centre d'operacions de ciberseguretat (SOC). Es proposen dues arquitectures diferents basades en l'anàlisi forense de fluxos de dades (NF3). La primera arquitectura empra tècniques de Ensemble Machine Learning mentre que la segona és una variant de Machine Learning de major complexitat algorítmica (lambda-NF3) que ofereix un marc de defensa de major robustesa enfront d'atacs adversaris. Totes dues propostes busquen automatitzar de manera efectiva la detecció de malware i la seua posterior gestió d'incidents mostrant uns resultats satisfactoris a aproximar el que s'ha denominat un SOC de pròxima generació i de computació cognitiva (NGC2SOC). La supervisió i monitoratge d'esdeveniments per a la protecció de les xarxes informàtiques d'una organització ha d'anar acompanyada de tècniques de visualització. En aquest cas, la tesi aborda la generació de representacions tridimensionals basades en mètriques orientades a la missió i procediments que usen un sistema expert basat en lògica difusa. Precisament, l'estat de l'art mostra serioses deficiències a l'hora d'implementar solucions de ciberdefensa que reflectisquen la rellevància de la missió, els recursos i comeses d'una organització per a una decisió més ben informada. El treball de recerca proporciona finalment dues àrees claus per a millorar la presa de decisions en ciberdefensa: un marc sòlid i complet de verificació i validació per a avaluar paràmetres de solucions i l'elaboració d'un conjunt de dades sintètiques que referencien unívocament les fases d'un ciberatac amb els estàndards Cyber Kill Chain i MITRE ATT & CK.[EN] This doctoral thesis performs a detailed analysis of the decision elements necessary to improve the cyber defence situation awareness with a special emphasis on the perception and understanding of the analyst of a cybersecurity operations center (SOC). Two different architectures based on the network flow forensics of data streams (NF3) are proposed. The first architecture uses Ensemble Machine Learning techniques while the second is a variant of Machine Learning with greater algorithmic complexity (lambda-NF3) that offers a more robust defense framework against adversarial attacks. Both proposals seek to effectively automate the detection of malware and its subsequent incident management, showing satisfactory results in approximating what has been called a next generation cognitive computing SOC (NGC2SOC). The supervision and monitoring of events for the protection of an organisation's computer networks must be accompanied by visualisation techniques. In this case, the thesis addresses the representation of three-dimensional pictures based on mission oriented metrics and procedures that use an expert system based on fuzzy logic. Precisely, the state-of-the-art evidences serious deficiencies when it comes to implementing cyber defence solutions that consider the relevance of the mission, resources and tasks of an organisation for a better-informed decision. The research work finally provides two key areas to improve decision-making in cyber defence: a solid and complete verification and validation framework to evaluate solution parameters and the development of a synthetic dataset that univocally references the phases of a cyber-attack with the Cyber Kill Chain and MITRE ATT & CK standards.Llopis Sánchez, S. (2023). Decision Support Elements and Enabling Techniques to Achieve a Cyber Defence Situational Awareness Capability [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19424

Analysing and visualising data sets of cybercrime investigations using structured occurrence nets

Ph. D. Thesis.Structured Occurrence Nets (SONs) are a Petri net based formalism for portraying the behaviour of complex evolving systems. As a concept, SONs are derived from Occurrence Nets (ONs). SONs provide a powerful framework for evolving system analysis and are supported by the existing SONCraft toolset. On the other hand, modelling of cybercrime investigations has become of interest in recent years, and large-scale criminal investigations have been considered as complex evolving systems. Right now, they present a significant challenge for police investigators and analysts. The current thesis contributes to addressing this challenge in two different ways: (i) by presenting an algorithm and an implemented tool that visualise data sets using maximal concurrency; and (ii) by detecting DNS tunnelling through a novel SON-based technique and tool. Moreover, the theoretical contribution of this thesis focuses on model extensions and abstraction; in particular, it introduces a new class of SONs based on multi-coloured tokens

A Formalised Approach to Designing Sonification Systems for Network-Security Monitoring

Sonification systems, in which data are represented through sound, have the potential to be useful in a number of network-security monitoring applications in Security Operations Centres (SOCs). Security analysts working in SOCs generally monitor networks using a combination of anomaly-detection techniques, Intrusion Detection Systems and data presented in visual and text-based forms. In the last two decades significant progress has been made in developing novel sonification systems to further support network-monitoring tasks, but many of these systems have not been sufficiently validated, and there is a lack of uptake in SOCs. Furthermore, little guidance exists on design requirements for the sonification of network data. In this paper, we identify the key role that sonification, if implemented correctly, could play in addressing shortcomings of traditional network-monitoring methods. Based on a review of prior research, we propose an approach to developing sonification systems for network monitoring. This approach involves the formalisation of a model for designing sonifications in this space; identification of sonification design aesthetics suitable for realtime network monitoring; and system refinement and validation through comprehensive user testing. As an initial step in this system development, we present a formalised model for designing sonifications for network-security monitoring. The application of this model is demonstrated through our development of prototype sonification systems for two different use-cases within network security monitoring

Behavioural Observation for Critical Infrastructure Security Support

Critical infrastructures include sectors such as energy resources, finance, food and water distribution, health, manufacturing and government services. In recent years, critical infrastructures have become increasingly dependent on ICT; more interconnected and are often, as a result, linked to the Internet. Consequently, this makes these systems more vulnerable and increases the threat of cyber-attack. In addition, the growing use of wireless networks means that infrastructures can be more susceptible to a direct digital attack than ever before. Traditionally, protecting against environmental threats was the main focus of critical infrastructure preservation. Now, however, with the emergence of cyber-attacks, the focus has changed and infrastructures are facing a different danger with potentially debilitating consequences. Current security techniques are struggling to keep up to date with the sheer volume of innovative and emerging attacks; therefore, considering fresh and adaptive solutions to existing computer security approaches is crucial. The research presented in this thesis, details the use of behavioural observation for critical infrastructure security support. Our observer system monitors an infrastructure’s behaviour and detects abnormalities, which are the result of a cyber-attack taking place. By observing subtle changes in system behaviours, an additional level of support for critical infrastructure security is provided through a plug-in device, which operates autonomously and has no negative impact on data flow. Behaviour is evaluated using mathematical classifications to assess the data and detect changes. The subsequent results achieved during the data classification process were high and successful. Our observer approach was able to accurately classify 98.138 % of the normal and abnormal system behaviours produced by a simulation of a critical infrastructure, using nine data classifiers

A Machine Learning Framework for Securing Patient Records

This research concerns the detection of abnormal data usage and unauthorised access in large-scale critical networks, specifically healthcare infrastructures. The focus of this research is safeguarding Electronic Patient Record (EPR)systems in particular. Privacy is a primary concern amongst patients due to the rising adoption of EPR systems. There is growing evidence to suggest that patients may withhold information from healthcare providers due to lack of Trust in the security of EPRs. Yet, patient record data must be available to healthcare providers at the point of care. Roles within healthcare organisations are dynamic and relying on access control is not sufficient. Access to EPR is often heavily audited within healthcare infrastructures. However, this data is regularly left untouched in a data silo and only ever accessed on an ad hoc basis. In addition, external threats need to be identified, such as phishing or social engineering techniques to acquire a clinician’s logon credentials. Without proactive monitoring of audit records, data breaches may go undetected. This thesis proposes a novel machine learning framework using a density-based local outlier detection model, in addition to employing a Human-in-the-Loop Machine Learning (HILML) approach. The density-based outlier detection model enables patterns in EPR data to be extracted to profile user behaviour and device interactions in order to detect and visualise anomalous activities. Employing a HILML model ensures that inappropriate activity is investigated and the data analytics is continuously improving. The novel framework is able to detect 156 anomalous behaviours in an unlabelled dataset of 1,007,727 audit logs