Security in peer-to-peer communication systems

P2PSIP (Peer-to-Peer Session Initiation Protocol) is a protocol developed by the IETF (Internet Engineering Task Force) for the establishment, completion and modi¿cation of communication sessions that emerges as a complement to SIP (Session Initiation Protocol) in environments where the original SIP protocol may fail for technical, ¿nancial, security, or social reasons. In order to do so, P2PSIP systems replace all the architecture of servers of the original SIP systems used for the registration and location of users, by a structured P2P network that distributes these functions among all the user agents that are part of the system. This new architecture, as with any emerging system, presents a completely new security problematic which analysis, subject of this thesis, is of crucial importance for its secure development and future standardization. Starting with a study of the state of the art in network security and continuing with more speci¿c systems such as SIP and P2P, we identify the most important security services within the architecture of a P2PSIP communication system: access control, bootstrap, routing, storage and communication. Once the security services have been identi¿ed, we conduct an analysis of the attacks that can a¿ect each of them, as well as a study of the existing countermeasures that can be used to prevent or mitigate these attacks. Based on the presented attacks and the weaknesses found in the existing measures to prevent them, we design speci¿c solutions to improve the security of P2PSIP communication systems. To this end, we focus on the service that stands as the cornerstone of P2PSIP communication systems¿ security: access control. Among the new designed solutions stand out: a certi¿cation model based on the segregation of the identity of users and nodes, a model for secure access control for on-the-¿y P2PSIP systems and an authorization framework for P2PSIP systems built on the recently published Internet Attribute Certi¿cate Pro¿le for Authorization. Finally, based on the existing measures and the new solutions designed, we de¿ne a set of security recommendations that should be considered for the design, implementation and maintenance of P2PSIP communication systems.Postprint (published version

A Secure Peer-to-Peer Application Framework

The nature of the Internet has changed dramatically. From a modest research network, it has evolved into one of the most important fabrics of our modern society, affecting the lives of billions each day. We rely on it for everything from performing our daily chores to accessing rich media and keeping in touch with our friends. Despite this change, service provisioning has largely remained intact. Services are provided in a centralized manner, resulting in bottlenecks and vulnerable collections of, often unwittingly, submitted sensitive information. Peer-to-peer (P2P) technologies have the potential to provide a better alternative for future networking. P2P services distribute the load from a single node to a network of peers, relying on the resources of the end-users themselves. Not only does it remove the bottlenecks, it has the potential to provide a more personal and safe networking environment. In this dissertation, we inspect the feasibility and implications of a generic, cross-application, P2P framework. We present the design and implementation of a framework that uses existing infrastructure and advanced networking protocols to create a secure environment. Using this framework, applications are able to benefit from P2P networking without having to deploy new infrastructure or implement complex connection- and identity management. Users benefit from using a single, strong, cross-application identity management and having better control over their data. This improves the trust within the system and enables new ways of dealing with security threats. We demonstrate the feasibility of the framework by evaluating the performance and usability of the prototype implementation. This provides a model for future networking applications and insight into the security and usability issues these will face

From Understanding Telephone Scams to Implementing Authenticated Caller ID Transmission

abstract: The telephone network is used by almost every person in the modern world. With the rise of Internet access to the PSTN, the telephone network today is rife with telephone spam and scams. Spam calls are significant annoyances for telephone users, unlike email spam, spam calls demand immediate attention. They are not only significant annoyances but also result in significant financial losses in the economy. According to complaint data from the FTC, complaints on illegal calls have made record numbers in recent years. Americans lose billions to fraud due to malicious telephone communication, despite various efforts to subdue telephone spam, scam, and robocalls. In this dissertation, a study of what causes the users to fall victim to telephone scams is presented, and it demonstrates that impersonation is at the heart of the problem. Most solutions today primarily rely on gathering offending caller IDs, however, they do not work effectively when the caller ID has been spoofed. Due to a lack of authentication in the PSTN caller ID transmission scheme, fraudsters can manipulate the caller ID to impersonate a trusted entity and further a variety of scams. To provide a solution to this fundamental problem, a novel architecture and method to authenticate the transmission of the caller ID is proposed. The solution enables the possibility of a security indicator which can provide an early warning to help users stay vigilant against telephone impersonation scams, as well as provide a foundation for existing and future defenses to stop unwanted telephone communication based on the caller ID information.Dissertation/ThesisDoctoral Dissertation Computer Science 201

Security for Decentralised Service Location - Exemplified with Real-Time Communication Session Establishment

Decentralised Service Location, i.e. finding an application communication endpoint based on a Distributed Hash Table (DHT), is a fairly new concept. The precise security implications of this approach have not been studied in detail. More importantly, a detailed analysis regarding the applicability of existing security solutions to this concept has not been conducted. In many cases existing client-server approaches to security may not be feasible. In addition, to understand the necessity for such an analysis, it is key to acknowledge that Decentralised Service Location has some unique security requirements compared to other P2P applications such as filesharing or live streaming. This thesis concerns the security challenges for Decentralised Service Location. The goals of our work are on the one hand to precisely understand the security requirements and research challenges for Decentralised Service Location, and on the other hand to develop and evaluate corresponding security mechanisms. The thesis is organised as follows. First, fundamentals are explained and the scope of the thesis is defined. Decentralised Service Location is defined and P2PSIP is explained technically as a prototypical example. Then, a security analysis for P2PSIP is presented. Based on this security analysis, security requirements for Decentralised Service Location and the corresponding research challenges -- i.e. security concerns not suitably mitigated by existing solutions -- are derived. Second, several decentralised solutions are presented and evaluated to tackle the security challenges for Decentralised Service Location. We present decentralised algorithms to enable availability of the DHTs lookup service in the presence of adversary nodes. These algorithms are evaluated via simulation and compared to analytical bounds. Further, a cryptographic approach based on self-certifying identities is illustrated and discussed. This approach enables decentralised integrity protection of location-bindings. Finally, a decentralised approach to assess unknown identities is introduced. The approach is based on a Web-of-Trust model. It is evaluated via prototypical implementation. Finally, the thesis closes with a summary of the main contributions and a discussion of open issues

Honeypots in the age of universal attacks and the Internet of Things

Today's Internet connects billions of physical devices. These devices are often immature and insecure, and share common vulnerabilities. The predominant form of attacks relies on recent advances in Internet-wide scanning and device discovery. The speed at which (vulnerable) devices can be discovered, and the device monoculture, mean that a single exploit, potentially trivial, can affect millions of devices across brands and continents. In an attempt to detect and profile the growing threat of autonomous and Internet-scale attacks against the Internet of Things, we revisit honeypots, resources that appear to be legitimate systems. We show that this endeavour was previously limited by a fundamentally flawed generation of honeypots and associated misconceptions. We show with two one-year-long studies that the display of warning messages has no deterrent effect in an attacked computer system. Previous research assumed that they would measure individual behaviour, but we find that the number of human attackers is orders of magnitude lower than previously assumed. Turning to the current generation of low- and medium-interaction honeypots, we demonstrate that their architecture is fatally flawed. The use of off-the-shelf libraries to provide the transport layer means that the protocols are implemented subtly differently from the systems being impersonated. We developed a generic technique which can find any such honeypot at Internet scale with just one packet for an established TCP connection. We then applied our technique and conducted several Internet-wide scans over a one-year period. By logging in to two SSH honeypots and sending specific commands, we not only revealed their configuration and patch status, but also found that many of them were not up to date. As we were the first to knowingly authenticate to honeypots, we provide a detailed legal analysis and an extended ethical justification for our research to show why we did not infringe computer-misuse laws. Lastly, we present honware, a honeypot framework for rapid implementation and deployment of high-interaction honeypots. Honware automatically processes a standard firmware image and can emulate a wide range of devices without any access to the manufacturers' hardware. We believe that honware is a major contribution towards re-balancing the economics of attackers and defenders by reducing the period in which attackers can exploit vulnerabilities at Internet scale in a world of ubiquitous networked `things'.Premium Research Studentship, Department of Computer Science and Technology, University of Cambridg

Systemarchitektur zur Ein- und Ausbruchserkennung in verschlüsselten Umgebungen

Das Internet hat sich mit einer beispiellosen Geschwindigkeit in den Lebensalltag integriert. Umfangreiche Dienste ermöglichen es, Bestellungen, finanzielle Transaktionen, etc. über das Netz durchzuführen. Auch traditionelle Dienste migrieren mehr und mehr in das Internet, wie bspw. Telefonie oder Fernsehen. Die finanziellen Werte, die hierbei umgesetzt werden, haben eine hohe Anziehungskraft auf Kriminelle: Angriffe im Internet sind aus einer sicheren Entfernung heraus möglich, unterschiedliches IT-Recht der verschiedenen Länder erschwert die grenzüberschreitende Strafverfolgung zusätzlich. Entsprechend hat sich in den letzten Jahren ein milliardenschwerer Untergrundmarkt im Internet etabliert. Um Systeme und Netze vor Angriffen zu schützen, befinden sich seit über 30 Jahren Verfahren zur Einbruchsdetektion in der Erforschung. Zahlreiche Systeme sind auf dem Markt verfügbar und gehören heute zu den Sicherheitsmechanismen jedes größeren Netzes. Trotz dieser Anstrengungen nimmt die Zahl von Sicherheitsvorfällen nicht ab, sondern steigt weiterhin an. Heutige Systeme sind nicht in der Lage, mit Herausforderungen wie zielgerichteten Angriffen, verschlüsselten Datenleitungen oder Innentätern umzugehen. Der Beitrag der vorliegenden Dissertation ist die Entwicklung einer Architektur zur Ein- und Ausbruchserkennung in verschlüsselten Umgebungen. Diese beinhaltet sowohl Komponenten zur Erkennung von extern durchgeführten Angriffen, als auch zur Identifikation von Innentätern. Hierbei werden statistische Methoden auf Basis einer verhaltensbasierten Detektion genutzt, so dass keine Entschlüsselung des Datenverkehrs erforderlich ist. Im Gegensatz zu bisherigen Methoden benötigt das System hierbei keine Lernphasen. Ausgehend von einem Szenario der IT-Struktur heutiger Unternehmen werden die Anforderungen an ein System zur Ein- und Ausbruchserkennung definiert. Da eine Detektion die Kenntnis entsprechender, messbarer Ansatzpunkte benötigt, erfolgt eine detaillierte Analyse einer Angriffsdurchführung. Auf dieser Basis sowie den Ergebnissen der Untersuchung des State-of-the-Art im Bereich der Ein- und Ausbruchserkennung wird identifiziert, warum heutige Systeme nicht in der Lage sind, ausgefeilte Angriffe zur erkennen. Anhand einer Betrachtung, welche Parameter bei verschlüsselten Verbindungen für eine Evaluation noch zur Verfügung stehen, werden Möglichkeiten zur Detektion von bösartigem Verhalten entwickelt. Hierauf basierend wird eine neue Architektur mit mehreren Teilmodulen zur Ein- und Ausbruchserkennung in verschlüsselten Umgebungen vorgestellt. Eine anschließende Evaluation zeigt die Funktionsfähigkeit der vorgestellten Architektur.The evolution of the Internet took place with a matchless speed over the past decades. Today, the Internet is established in numerous areas of everyday life. Purchase orders or money transfers are only two examples. The financial values which are moved over the Internet are alluring criminals. Attacks with the aid of the Internet can be executed from a safe distance, different IT laws of the countries hamper the transboundary criminal prosecution. Therefore, an underground market worth billions has been established over the past years. For the protection of systems and networks, procedures for intrusion detection are under development for more than 30 years. Numerous systems are available and are integral security components in every bigger network today. However, even with these strong efforts, the number of security incidents is steadily increasing. Todays systems are not able to cope with challenges like targeted attacks, encrypted communication and connections or the insider threat. The contribution of this thesis is the design and development of an architecture for intrusion and extrusion detection in encrypted environments. The architecture consists of components for the detection of external attacks as well as the identification of insiders. Statistical methods and behavior-based techniques are used, therefore there is no need for a deciphering of the data traffic. In contrast to existing approaches, the proposed architecture does not need a learning phase. Based on a scenario of the IT infrastructure of a company, the requirements for a system for intrusion and extrusion detection are defined. Because measuring points must be located for being able to carry out a detection, an in-depth analysis of the execution of an attack is done. Afterwards, reasons for the failure of the detection of sophisticated attacks by current systems are identified based on an evaluation of the State-of-the-Art of in- and extrusion detection. An examination of encrypted network connections is used to deduce parameters which are still available after an encryption and which can be used for a detection of malicious behavior. The identified starting points are used for the development of a new architecture consisting of multiple modules for intrusion as well as extrusion detection in encrypted environments. A subsequent evaluation verifies the efficiency of the proposed architecture

On Security and Privacy for Networked Information Society : Observations and Solutions for Security Engineering and Trust Building in Advanced Societal Processes

Our society has developed into a networked information society, in which all aspects of human life are interconnected via the Internet — the backbone through which a significant part of communications traffic is routed. This makes the Internet arguably the most important piece of critical infrastructure in the world. Securing Internet communications for everyone using it is extremely important, as the continuing growth of the networked information society relies upon fast, reliable and secure communications. A prominent threat to the security and privacy of Internet users is mass surveillance of Internet communications. The methods and tools used to implement mass surveillance capabilities on the Internet pose a danger to the security of all communications, not just the intended targets. When we continue to further build the networked information upon the unreliable foundation of the Internet we encounter increasingly complex problems,which are the main focus of this dissertation. As the reliance on communication technology grows in a society, so does the importance of information security. At this stage, information security issues become separated from the purely technological domain and begin to affect everyone in society. The approach taken in this thesis is therefore both technical and socio-technical. The research presented in this PhD thesis builds security in to the networked information society and provides parameters for further development of a safe and secure networked information society. This is achieved by proposing improvements on a multitude of layers. In the technical domain we present an efficient design flow for secure embedded devices that use cryptographic primitives in a resource-constrained environment, examine and analyze threats to biometric passport and electronic voting systems, observe techniques used to conduct mass Internet surveillance, and analyze the security of Finnish web user passwords. In the socio-technical domain we examine surveillance and how it affects the citizens of a networked information society, study methods for delivering efficient security education, examine what is essential security knowledge for citizens, advocate mastery over surveillance data by the targeted citizens in the networked information society, and examine the concept of forced trust that permeates all topics examined in this work.Yhteiskunta, jossa elämme, on muovautunut teknologian kehityksen myötä todelliseksi tietoyhteiskunnaksi. Monet verkottuneen tietoyhteiskunnan osa-alueet ovat kokeneet muutoksen tämän kehityksen seurauksena. Tämän muutoksen keskiössä on Internet: maailmanlaajuinen tietoverkko, joka mahdollistaa verkottuneiden laitteiden keskenäisen viestinnän ennennäkemättömässä mittakaavassa. Internet on muovautunut ehkä keskeisimmäksi osaksi globaalia viestintäinfrastruktuuria, ja siksi myös globaalin viestinnän turvaaminen korostuu tulevaisuudessa yhä enemmän. Verkottuneen tietoyhteiskunnan kasvu ja kehitys edellyttävät vakaan, turvallisen ja nopean viestintäjärjestelmän olemassaoloa. Laajamittainen tietoverkkojen joukkovalvonta muodostaa merkittävän uhan tämän järjestelmän vakaudelle ja turvallisuudelle. Verkkovalvonnan toteuttamiseen käytetyt menetelmät ja työkalut eivät vain anna mahdollisuutta tarkastella valvonnan kohteena olevaa viestiliikennettä, vaan myös vaarantavat kaiken Internet-liikenteen ja siitä riippuvaisen toiminnan turvallisuuden. Kun verkottunutta tietoyhteiskuntaa rakennetaan tämän kaltaisia valuvikoja ja haavoittuvuuksia sisältävän järjestelmän varaan, keskeinen uhkatekijä on, että yhteiskunnan ydintoiminnot ovat alttiina ulkopuoliselle vaikuttamiselle. Näiden uhkatekijöiden ja niiden taustalla vaikuttavien mekanismien tarkastelu on tämän väitöskirjatyön keskiössä. Koska työssä on teknisen sisällön lisäksi vahva yhteiskunnallinen elementti, tarkastellaan tiukan teknisen tarkastelun sijaan aihepiirä laajemmin myös yhteiskunnallisesta näkökulmasta. Tässä väitöskirjassa pyritään rakentamaan kokonaiskuvaa verkottuneen tietoyhteiskunnan turvallisuuteen, toimintaan ja vakauteen vaikuttavista tekijöistä, sekä tuomaan esiin uusia ratkaisuja ja avauksia eri näkökulmista. Työn tavoitteena on osaltaan mahdollistaa entistä turvallisemman verkottuneen tietoyhteiskunnan rakentaminen tulevaisuudessa. Teknisestä näkökulmasta työssä esitetään suunnitteluvuo kryptografisia primitiivejä tehokkaasti hyödyntäville rajallisen laskentatehon sulautetuviiille järjestelmille, analysoidaan biometrisiin passeihin, kansainväliseen passijärjestelmään, sekä sähköiseen äänestykseen kohdistuvia uhkia, tarkastellaan joukkovalvontaan käytettyjen tekniikoiden toimintaperiaatteita ja niiden aiheuttamia uhkia, sekä tutkitaan suomalaisten Internet-käyttäjien salasanatottumuksia verkkosovelluksissa. Teknis-yhteiskunnallisesta näkökulmasta työssä tarkastellaan valvonnan teoriaa ja perehdytään siihen, miten valvonta vaikuttaa verkottuneen tietoyhteiskunnan kansalaisiin. Lisäksi kehitetään menetelmiä parempaan tietoturvaopetukseen kaikilla koulutusasteilla, määritellään keskeiset tietoturvatietouden käsitteet, tarkastellaan mahdollisuutta soveltaa tiedon herruuden periaatetta verkottuneen tietoyhteiskunnan kansalaisistaan keräämän tiedon hallintaan ja käyttöön, sekä tutkitaan luottamuksen merkitystä yhteiskunnan ydintoimintojen turvallisuudelle ja toiminnalle, keskittyen erityisesti pakotetun luottamuksen vaikutuksiin

Unpicking the semes: Power, resistance, and the Internet

The Internet was a catalyst for refiguring the previous models of media relationships. For many, the Internet is a medium that liberates individuals from the centralised and asymmetrical power structures of traditional mass media and other social institutions in particular, the boundaries set by the nation and the state. For other people, the Internet increases the capacity for surveillance and control. This dissertation argues for a fluid conception of the operations of power and resistance on the Internet that takes into account the various discourses which play a part in determining agency and subjectivity. It examines and balances the narratives of liberation and oppression against each other: for, just as the developments in Internet technology contribute to changes in discourse, so too existing or prior discursive limits and relations of power affect Internet culture and technology. In the process of analysing the interplay of different discourses on the Internet, this dissertation takes into account transnational and national cultural flows and the insights that conceptual work on globalisation, transnationalism, and cosmopolitanism can provide. The case studies are concerned with change and centre on the use of the Internet to effect this change; they include: the Singaporean Internet, a 'thread' about Asian culture and Australia, the representation of oppression and the formation of Chinese diasporic collectivities, and anti capitalist networks. Through these case studies, the dissertation examines the degree to which the nation-state can regulate and affect the discourses at play on the Internet as well as the agency of participants in countering and maintaining these discourses. This dissertation also analyses activists' use of the Internet to form transnational networks. It discusses the limitations of their work including problems with representation