Understanding Flaws in the Deployment and Implementation of Web Encryption

In recent years, the web has switched from using the unencrypted HTTP protocol to using encrypted communications. Primarily, this resulted in increasing deployment of TLS to mitigate information leakage over the network. This development has led many web service operators to mistakenly think that migrating from HTTP to HTTPS will magically protect them from information leakage without any additional effort on their end to guar- antee the desired security properties. In reality, despite the fact that there exists enough infrastructure in place and the protocols have been “tested” (by virtue of being in wide, but not ubiquitous, use for many years), deploying HTTPS is a highly challenging task due to the technical complexity of its underlying protocols (i.e., HTTP, TLS) as well as the complexity of the TLS certificate ecosystem and this of popular client applications such as web browsers. For example, we found that many websites still avoid ubiquitous encryption and force only critical functionality and sensitive data access over encrypted connections while allowing more innocuous functionality to be accessed over HTTP. In practice, this approach is prone to flaws that can expose sensitive information or functionality to third parties. Thus, it is crucial for developers to verify the correctness of their deployments and implementations. In this dissertation, in an effort to improve users’ privacy, we highlight semantic flaws in the implementations of both web servers and clients, caused by the improper deployment of web encryption protocols. First, we conduct an in-depth assessment of major websites and explore what functionality and information is exposed to attackers that have hijacked a user’s HTTP cookies. We identify a recurring pattern across websites with partially de- ployed HTTPS, namely, that service personalization inadvertently results in the exposure of private information. The separation of functionality across multiple cookies with different scopes and inter-dependencies further complicates matters, as imprecise access control renders restricted account functionality accessible to non-secure cookies. Our cookie hijacking study reveals a number of severe flaws; for example, attackers can obtain the user’s saved address and visited websites from e.g., Google, Bing, and Yahoo allow attackers to extract the contact list and send emails from the user’s account. To estimate the extent of the threat, we run measurements on a university public wireless network for a period of 30 days and detect over 282K accounts exposing the cookies required for our hijacking attacks. Next, we explore and study security mechanisms purposed to eliminate this problem by enforcing encryption such as HSTS and HTTPS Everywhere. We evaluate each mechanism in terms of its adoption and effectiveness. We find that all mechanisms suffer from implementation flaws or deployment issues and argue that, as long as servers continue to not support ubiquitous encryption across their entire domain, no mechanism can effectively protect users from cookie hijacking and information leakage. Finally, as the security guarantees of TLS (in turn HTTPS), are critically dependent on the correct validation of X.509 server certificates, we study hostname verification, a critical component in the certificate validation process. We develop HVLearn, a novel testing framework to verify the correctness of hostname verification implementations and use HVLearn to analyze a number of popular TLS libraries and applications. To this end, we found 8 unique violations of the RFC specifications. Several of these violations are critical and can render the affected implementations vulnerable to man-in-the-middle attacks

Blockchain-Enabled DPKI Framework

Public Key Infrastructures (PKIs), which rely on digital signature technology and establishment of trust and security association parameters between entities, allow entities to interoperate with authentication proofs, using standardized digital certificates (with X.509v3 as the current reference). Despite PKI technology being used by many applications for their security foundations (e.g. WEB/HTTPS/TLS, Cloud-Enabled Services, LANs/WLANs Security, VPNs, IP-Security), there are several concerns regarding their inherent design assumptions based on a centralized trust model. To avoid some problems and drawbacks that emerged from the centralization assumptions, a Decentralized Public Key Infrastructure (DPKI), is an alternative approach. The main idea for DPKIs is the ability to establish trust relations between all parties, in a web-of-trust model, avoiding centralized authorities and related root-of-trust certificates. As a possible solution for DPKI frameworks, the Blockchain technology, as an enabler solution, can help overcome some of the identified PKI problems and security drawbacks. Blockchain-enabled DPKIs can be designed to address a fully decentralized ledger for managed certificates, providing data-replication with strong consistency guarantees, and fairly distributed trust management properties founded on a P2P trust model. In this approach, typical PKI functions are supported cooperatively, with validity agreement based on consistency criteria, for issuing, verification and revocation of X509v3 certificates. It is also possible to address mechanisms to provide rapid reaction of principals in the verification of traceable, shared and immutable history logs of state-changes related to the life-cycle of certificates, with certificate validation rules established consistently by programmable Smart Contracts executed by peers. In this dissertation we designed, implemented and evaluated a Blockchain-Enabled Decentralized Public Key Infrastructure (DPKI) framework, providing an implementation prototype solution that can be used and to support experimental research. The proposal is based on a framework instantiating a permissioned collaborative consortium model, using the service planes supported in an extended Blockchain platform leveraged by the Hyperledger Fabric (HLF) solution. In our proposed DPKI framework model, X509v3 certificates are issued and managed following security invariants, processing rules, managing trust assumptions and establishing consistency metrics, defined and executed in a decentralized way by the Blockchain nodes, using Smart Contracts. Certificates are issued cooperatively and can be issued with group-oriented threshold-based Byzantine fault-tolerant (BFT) signatures, as group-oriented authentication proofs. The Smart Contracts dictate how Blockchain peers participate consistently in issuing, signing, attestation, validation and revocation processes. Any peer can validate certificates obtaining their consistent states consolidated in closed blocks in a Meckle tree structure maintained in the Blockchain. State-transition operations are managed with serializability guarantees, provided by Byzantine Fault Tolerant (BFT) consensus primitives

The Impact of DNSSEC on the Internet Landscape

In this dissertation we investigate the security deficiencies of the Domain Name System (DNS) and assess the impact of the DNSSEC security extensions. DNS spoofing attacks divert an application to the wrong server, but are also used routinely for blocking access to websites. We provide evidence for systematic DNS spoofing in China and Iran with measurement-based analyses, which allow us to examine the DNS spoofing filters from vantage points outside of the affected networks. Third-parties in other countries can be affected inadvertently by spoofing-based domain filtering, which could be averted with DNSSEC. The security goals of DNSSEC are data integrity and authenticity. A point solution called NSEC3 adds a privacy assertion to DNSSEC, which is supposed to prevent disclosure of the domain namespace as a whole. We present GPU-based attacks on the NSEC3 privacy assertion, which allow efficient recovery of the namespace contents. We demonstrate with active measurements that DNSSEC has found wide adoption after initial hesitation. At server-side, there are more than five million domains signed with DNSSEC. A portion of them is insecure due to insufficient cryptographic key lengths or broken due to maintenance failures. At client-side, we have observed a worldwide increase of DNSSEC validation over the last three years, though not necessarily on the last mile. Deployment of DNSSEC validation on end hosts is impaired by intermediate caching components, which degrade the availability of DNSSEC. However, intermediate caches contribute to the performance and scalability of the Domain Name System, as we show with trace-driven simulations. We suggest that validating end hosts utilize intermediate caches by default but fall back to autonomous name resolution in case of DNSSEC failures.In dieser Dissertation werden die Sicherheitsdefizite des Domain Name Systems (DNS) untersucht und die Auswirkungen der DNSSEC-Sicherheitserweiterungen bewertet. DNS-Spoofing hat den Zweck eine Anwendung zum falschen Server umzuleiten, wird aber auch regelmäßig eingesetzt, um den Zugang zu Websites zu sperren. Durch messbasierte Analysen wird in dieser Arbeit die systematische Durchführung von DNS-Spoofing-Angriffen in China und im Iran belegt, wobei sich die Messpunkte außerhalb der von den Sperrfiltern betroffenen Netzwerke befinden. Es wird gezeigt, dass Dritte in anderen Ländern durch die Spoofing-basierten Sperrfilter unbeabsichtigt beeinträchtigt werden können, was mit DNSSEC verhindert werden kann. Die Sicherheitsziele von DNSSEC sind Datenintegrität und Authentizität. Die NSEC3-Erweiterung sichert zudem die Privatheit des Domainnamensraums, damit die Inhalte eines DNSSEC-Servers nicht in Gänze ausgelesen werden können. In dieser Arbeit werden GPU-basierte Angriffsmethoden auf die von NSEC3 zugesicherte Privatheit vorgestellt, die eine effiziente Wiederherstellung des Domainnamensraums ermöglichen. Ferner wird mit aktiven Messmethoden die Verbreitung von DNSSEC untersucht, die nach anfänglicher Zurückhaltung deutlich zugenommen hat. Auf der Serverseite gibt es mehr als fünf Millionen mit DNSSEC signierte Domainnamen. Ein Teil davon ist aufgrund von unzureichenden kryptographischen Schlüssellängen unsicher, ein weiterer Teil zudem aufgrund von Wartungsfehlern nicht mit DNSSEC erreichbar. Auf der Clientseite ist der Anteil der DNSSEC-Validierung in den letzten drei Jahren weltweit gestiegen. Allerdings ist hierbei offen, ob die Validierung nahe bei den Endgeräten stattfindet, um unvertraute Kommunikationspfade vollständig abzusichern. Der Einsatz von DNSSEC-Validierung auf Endgeräten wird durch zwischengeschaltete DNS-Cache-Komponenten erschwert, da hierdurch die Verfügbarkeit von DNSSEC beeinträchtigt wird. Allerdings tragen zwischengeschaltete Caches zur Performance und Skalierbarkeit des Domain Name Systems bei, wie in dieser Arbeit mit messbasierten Simulationen gezeigt wird. Daher sollten Endgeräte standardmäßig die vorhandene DNS-Infrastruktur nutzen, bei Validierungsfehlern jedoch selbständig die DNSSEC-Zielserver anfragen, um im Cache gespeicherte, fehlerhafte DNS-Antworten zu umgehen

Multilingual interactive integrated multimedia based e-commerce

As we approach the end of the twentieth century, E-commerce is a critical force shaping the world of today and tomorrow. E-commerce have introduced a new society where people can buy freely, anywhere, at anytime, across the globe on the web. There seems to be a market for consultants and outsourcing purveyors who will take your money and put together an online business for you. These are all very different markets, however. As lot of people speak different language than English, the concept of Multilingual Technology is essential. The primary purpose of this research paper is to study the Integrated Multimedia interaction with today\u27s technology secondary purpose is to check out the Application of this technology in E -Commerce with the help of Multilingual technology. Multilingual-based E-commerce would prompt more widespread use of the types of services now available and prompt the development of new and better services and the benefits brought by information, technology, and information services available will be magnified and extended globally

Trust on the semantic web

The Semantic Web is a vision to create a “web of knowledge”; an extension of the Web as we know it which will create an information space which will be usable by machines in very rich ways. The technologies which make up the Semantic Web allow machines to reason across information gathered from the Web, presenting only relevant results and inferences to the user. Users of the Web in its current form assess the credibility of the information they gather in a number of different ways. If processing happens without the user being able to check the source and credibility of each piece of information used in the processing, the user must be able to trust that the machine has used trustworthy information at each step of the processing. The machine should therefore be able to automatically assess the credibility of each piece of information it gathers from the Web. A case study on advanced checks for website credibility is presented, and the site presented in the case presented is found to be credible, despite failing many of the checks which are presented. A website with a backend based on RDF technologies is constructed. A better understanding of RDF technologies and good knowledge of the RAP and Redland RDF application frameworks is gained. The second aim of constructing the website was to gather information to be used for testing various trust metrics. The website did not gain widespread support, and therefore not enough data was gathered for this. Techniques for presenting RDF data to users were also developed during website development, and these are discussed. Experiences in gathering RDF data are presented next. A scutter was successfully developed, and the data smushed to create a database where uniquely identifiable objects were linked, even where gathered from different sources. Finally, the use of digital signature as a means of linking an author and content produced by that author is presented. RDF/XML canonicalisation is discussed in the provision of ideal cryptographic checking of RDF graphs, rather than simply checking at the document level. The notion of canonicalisation on the semantic, structural and syntactic levels is proposed. A combination of an existing canonicalisation algorithm and a restricted RDF/XML dialect is presented as a solution to the RDF/XML canonicalisation problem. We conclude that a trusted Semantic Web is possible, with buy in from publishing and consuming parties

Internatsionaliseerumise protsessid Hiina firmades: teadmuse roll

Väitekirja elektrooniline versioon ei sisalda empiirilisi uuringuid.Kasutades nii kvantitatiivseid kui ka kvalitatiivseid meetodeid ühendades võrdlevaid uuringuid ja pikaajalisi analüüse, on doktoritöö eesmärgiks välja selgitada teadmuse roll Hiina ettevõtete internatsionaliseerumise protsessides. Töös töödeldakse süstemaatiliselt, Hiina kontekstist lähtuvalt, rahvusvahelistumise uuringuid, otse allikast saadud ettevõttetasandil olevaid andmeid ning viie originaal väljaande tulemusi, mis on ühendatud vastavalt teenima sama eemärki, ent neil on eri teadusuuringulised eesmärgid, mis keskenduvad erinevatele aspektidele, kasutades erinevaid meetodeid. Doktoritöö teoreetiline osa põhineb rahvusvahelistumise teemalisel kirjandusel, eriti Uppsala mudelil ja Born Global mudelil. Samuti keskendub töö kirjandus ettevõtete välismaiste kogemuslikule teadmusele ja selle omandamisele. Autor leiab, et välisturu teadmus on oluline ettevõtete rahvusvahelistumise seisukohast. Selle puudumise korral võib aeglustuda rahvusvahelistumise protsess ja põhjustada ettevõtete esialgset sisenemist lähiriikidesse, kasutades selleks kõige lihtsamaid sisenemise mudeleid. Ettevõtted võivad omandada välisturule sisenemise teadmisi, mitte üksnes otsesest turukogemusest, vaid ka palgates teatud liiki uut personali, tehes koostööd jne. Välisturu tundmine võib positiivselt mõjutada ettevõtete rahvusvahelistumise protsessi, kuid ei pruugi tagada edu. Ettevõtete rahvusvaheliseerumine ei pruugi olla sujuv, vaid pigem lainekujuline protsess, mis hõlmab endas oodatud ja radikaalseid muututusi. Kasutades esmaallikatasandist pärinevaid ettevõtte andmeid ning analüüsides neid kombineeritud meetodite abil, selgus, et nii Hiina BG ja NBG ettevõtted rahvusvahelistusid esilagu edukalt, vaatamata puuduvale teadmusele. Madal teadmuse tase ei mõjuta nende rahvusvahelistumise kiirust, kuid kõik ettevõtted kasutasid eksportimist kui välismaist töörežiimi. Mõlemad BG-d ja NBG-d valivad kultuuriliselt ja geograafiliselt kaugemad riigid, mis on suurema elanikkonna ja arenenuma majandusega. Pärast sisenemist oma kolme esimesele välisturule, ettevõtted hakkavad omandama teadmisi, mis hakkavad mõjutama nende edasisi välisturgudele laienemise strateegiaid. Muutuste ja kriisiperioodil määrab teadmuse tase, kas ettevõtted lahkuvad välisturgudelt ning kui edukas on nende taassisenemine välisturule.teadmisedettevõttedrahvusvahelistuminekvantitatiivsed uurimismeetodidkvalitatiivsed uurimismeetodidvõrdlevuuringudHiinaUsing both quantitative and qualitative methods, and combining comparative studies and longitudinal analysis, the aim of this dissertation is to identify the role of knowledge in internationalization processes of Chinese firms. By systematically reviewing the literature on internationalization studies in the Chinese context, and by using firsthand firm-level data, five original publications result, which are united under the same goal yet have separate research tasks that focus on different aspects using various methodologies.The theoretical part of this thesis is based on the internationalization literature, particular on streams of Uppsala model and Born global model. It also focuses on the literature regarding firms’ foreign experiential knowledge and its acquisition. Author concludes that foreign market knowledge is important to firms’ internationalization. A lack of it may slow down the internationalization process and cause firms to initially enter the closest countries, using the simplest entry modes. Firms may acquire foreign market knowledge not only through direct market experience, but also by hiring certain types of personnel, cooperation, and so on. Foreign market knowledge may positively affect firms’ internationalization processes, but does not guarantee success. Firms’ internationalization is not necessarily a smooth path, but rather a wave- shaped process that involves expected and radical changes.Through the mixed-methods, by using first-hand firm level data, this research discovers that both Chinese BGs and NBGs initially internationalize successfully, despite lacking knowledge. Low knowledge levels do not affect their internationalization speed, but firms all use exporting as their foreign operation mode. Both BGs and NBGs select culturally and geographically more distant countries that have a higher population and more advanced economic development. After entering their first three foreign markets, firms start to gain knowledge, which affects their foreign expansion strategy going forward. During periods of radical change and crisis, knowledge level determines decisions relating to the firms’ foreign market exit, and the success of reentry.knowledgefirmsinternationalisationquantitative research methodsqualitative research methodscomparative researchChin