Security Issues in OAuth 2.0 SSO Implementations

Abstract. Many Chinese websites (relying parties) use OAuth 2.0 as the basis of a single sign-on service to ease password management for users. Many sites support five or more different OAuth 2.0 identity providers, giving users choice in their trust point. However, although OAuth 2.0 has been widely implemented (particularly in China), little attention has been paid to security in practice. In this paper we report on a detailed study of OAuth 2.0 implementation security for ten major identity providers and 60 relying parties, all based in China. This study reveals two critical vulnerabilities present in many implementations, both allowing an attacker to control a victim user’s accounts at a relying party without knowing the user’s account name or password. We provide sim-ple, practical recommendations for identity providers and relying parties to enable them to mitigate these vulnerabilities. The vulnerabilities have been reported to the parties concerned.

Mitigating CSRF attacks on OAuth 2.0 Systems

Many millions of users routinely use Google, Facebook and Microsoft to log in to websites supporting OAuth 2.0 and/or OpenID Connect. The security of OAuth 2.0 and OpenID Connect is therefore of critical importance. Unfortunately, as previous studies have shown, real-world implementations of both schemes are often vulnerable to attack, and in particular to crosssite request forgery (CSRF) attacks. In this paper we propose a new and practical technique which can be used to mitigate CSRF attacks against both OAuth 2.0 and OpenID Connect. Index Terms-OAuth 2.0, OpenID Connect, CSRF

Automated Security Testing for Identity Management of Large-scale Digital Infrastructures

Ensuring the security of an organization's digital assets against cyber threats is critical in today's technology-driven world. Regular security testing is one of the measures that can help assess the effectiveness of security controls, identify vulnerabilities, and strengthen the overall cybersecurity posture. Identity Management (IdM) protocols such as Security Assertion Markup Language 2.0, OpenID Connect, and OAuth 2.0 play a crucial role in protecting against identity theft, fraud, and security breaches. Also, following the Best Current Practices introduced by the standards to enhance the security of IdM protocols is essential to minimize the risk of unauthorized access, data breaches, and other security threats and to maintain compliance with regulatory requirements, and build trust with users and stakeholders. However, deploying these protocols can be challenging due to the complexity in designing, developing and implementing cryptographic mechanisms. The implementation of IdM protocols encounters three significant obstacles: fragmented security information, rapidly evolving threat environment, and the need for a controlled testing environment. Security testers must stay up-to-date with emerging threats and establish an appropriate testing infrastructure to guarantee the security and robustness of IdM implementations, while also minimizing the possibility of security incidents that could adversely affect operations. Automated security testing plays a crucial role in addressing security concerns, particularly as the intricate functional aspects of IdM solutions contribute to their complexity. It is essential to prioritize automation to bridge the cybersecurity skills gap among IT professionals. In this thesis, we propose Micro-Id-Gym (MIG), a framework that offers (i) an easy way to configure and reproduce the IdM production environment in a sandbox, allowing hands-on experiences with potentially impactful security tests that may winder availability of services and (ii) automatic security testing of IdM implementations together with suggestions for mitigations to avoid identified vulnerabilities. MIG provides a set of security testing tools for creating, executing, and analyzing security test cases through MIG-L, a declarative test specification language. We have evaluated the effectiveness of MIG by conducting experiments to assess the accuracy in supporting detection of relevant vulnerabilities in the implementation of IdM protocols. We utilized MIG to conduct security analyses across various corporate scenarios and projects, identifying vulnerabilities and responsibly disclosing them through bug bounty programs. Our findings were recognized by the providers, who awarded us both monetary compensation and public recognition. Overall, MIG can help organizations establish a robust and agile security testing strategy, supported by suitable infrastructure and testing procedures, that can ensure the security and resilience of their IdM implementations

PESTO: Proactively Secure Distributed Single Sign-On, or How to Trust a Hacked Server

Single Sign-On (SSO) is becoming an increasingly popular authentication method for users that leverages a trusted Identity Provider (IdP) to bootstrap secure authentication tokens from a single user password. It alleviates some of the worst security issues of passwords, as users no longer need to memorize individual passwords for all service providers, and it removes the burden of these service to properly protect huge password databases. However, SSO also introduces a single point of failure. If compromised, the IdP can impersonate all users and learn their master passwords. To remedy this risk while preserving the advantages of SSO, Agrawal et al. (CCS\u2718) recently proposed a distributed realization termed PASTA (password-authenticated threshold authentication) which splits the role of the IdP across $n$ servers. While PASTA is a great step forward and guarantees security as long as not all servers are corrupted, it uses a rather inflexible corruption model: servers cannot be corrupted adaptively and --- even worse --- cannot recover from corruption. The latter is known as proactive security and allows servers to re-share their keys, thereby rendering all previously compromised information useless. In this work, we improve upon the work of PASTA and propose a distributed SSO protocol with proactive and adaptive security (PESTO), guaranteeing security as long as not all servers are compromised at the same time. We prove our scheme secure in the UC framework which is known to provide the best security guarantees for password-based primitives. The core of our protocol are two new primitives we introduce: partially-oblivious distributed PRFs and a class of distributed signature schemes. Both allow for non-interactive refreshs of the secret key material and tolerate adaptive corruptions. We give secure instantiations based on the gap one-more BDH and RSA assumption respectively, leading to a highly efficient 2-round PESTO protocol. We also present an implementation and benchmark of our scheme in Java, realizing OAuth-compatible bearer tokens for SSO, demonstrating the viability of our approach

iUC: Flexible Universal Composability Made Simple

Proving the security of complex protocols is a crucial and very challenging task. A widely used approach for reasoning about such protocols in a modular way is universal composability. A perfect model for universal composability should provide a sound basis for formal proofs and be very flexible in order to allow for modeling a multitude of different protocols. It should also be easy to use, including useful design conventions for repetitive modeling aspects, such as corruption, parties, sessions, and subroutine relationships, such that protocol designers can focus on the core logic of their protocols. While many models for universal composability exist, including the UC, GNUC, and IITM models, none of them has achieved this ideal goal yet. As a result, protocols cannot be modeled faithfully and/or using these models is a burden rather than a help, often even leading to underspecified protocols and formally incorrect proofs. Given this dire state of affairs, the goal of this work is to provide a framework for universal composability which combines soundness, flexibility, and usability in an unmatched way. Developing such a security framework is a very difficult and delicate task, as the long history of frameworks for universal composability shows. We build our framework, called iUC, on top of the IITM model, which already provides soundness and flexibility while lacking sufficient usability. At the core of iUC is a single simple template for specifying essentially arbitrary protocols in a convenient, formally precise, and flexible way. We illustrate the main features of our framework with example functionalities and realizations

Modelling escalation of attacks in federated identity management

PhD ThesisFederated Identity Management (FIM) is an increasingly prevalent method for authenticating users online. FIM offloads the authentication burden from a Service Provider (SP) to an Identity Provider (IdP) that the SP trusts. The different entities involved in the FIM process are referred to as stakeholders. The benefits of FIM to stakeholders are clear, such as the ability for users to use Single Sign-On. However, the security of FIM also has to be evaluated. Attacks on one point in a FIM system can lead to other attacks being possible, and detecting those attacks can be hard just from modelling the functionality of the FIM system. Attacks in which the effect of one attack can become the cause for another attack are referred to in this thesis as escalating attacks. The overall research question this thesis revolves around: how can we model escalating attacks to detect attacks which are possible through an adversary first launching another attack, and present causality of attacks to the FIM stakeholders involved? This thesis performs a survey of existing attacks in FIM. We categorise attacks on FIM using a taxonomy of our own design. This survey is the first attempt at categorising attacks that target FIM using a taxonomy. Some attacks can have an effect that causes another attack to be possible in ways that are difficult to predict. We consider a case study involving OAuth 2.0 (provided by existing literature), as a basis for modelling attack escalation. We then seek to present a language for modelling FIM systems and attacker manipulations on those systems. We find that FIM systems can be generalised for the purpose of a programmatic logical analysis. In addition, attacker manipulations on a system can be broken down using an existing conceptual framework called Malicious and Accidental Fault Tolerance (MAFTIA). Using a generalised FIM system model and MAFTIA, we can express a complex interlinking of attacks informed by case studies in FIM security analysis. This is the first attempt to model FIM systems generally and apply logical analysis to that model. Finally, we show how causality of attacks can be analysed using attack trees. We find that any solutions to an escalating attack can be expressed using a tree model which conforms to existing research on attack trees. Our approach is the first attempt of modelling attacks on FIM systems through the use of attack trees. We consider stakeholder attribution and cost analysis as concrete methods for analysing attack trees

Segurança e privacidade em terminologia de rede

Security and Privacy are now at the forefront of modern concerns, and drive a significant part of the debate on digital society. One particular aspect that holds significant bearing in these two topics is the naming of resources in the network, because it directly impacts how networks work, but also affects how security mechanisms are implemented and what are the privacy implications of metadata disclosure. This issue is further exacerbated by interoperability mechanisms that imply this information is increasingly available regardless of the intended scope. This work focuses on the implications of naming with regards to security and privacy in namespaces used in network protocols. In particular on the imple- mentation of solutions that provide additional security through naming policies or increase privacy. To achieve this, different techniques are used to either embed security information in existing namespaces or to minimise privacy ex- posure. The former allows bootstraping secure transport protocols on top of insecure discovery protocols, while the later introduces privacy policies as part of name assignment and resolution. The main vehicle for implementation of these solutions are general purpose protocols and services, however there is a strong parallel with ongoing re- search topics that leverage name resolution systems for interoperability such as the Internet of Things (IoT) and Information Centric Networks (ICN), where these approaches are also applicable.Segurança e Privacidade são dois topicos que marcam a agenda na discus- são sobre a sociedade digital. Um aspecto particularmente subtil nesta dis- cussão é a forma como atribuímos nomes a recursos na rede, uma escolha com consequências práticas no funcionamento dos diferentes protocols de rede, na forma como se implementam diferentes mecanismos de segurança e na privacidade das várias partes envolvidas. Este problema torna-se ainda mais significativo quando se considera que, para promover a interoperabili- dade entre diferentes redes, mecanismos autónomos tornam esta informação acessível em contextos que vão para lá do que era pretendido. Esta tese foca-se nas consequências de diferentes políticas de atribuição de nomes no contexto de diferentes protocols de rede, para efeitos de segurança e privacidade. Com base no estudo deste problema, são propostas soluções que, através de diferentes políticas de atribuição de nomes, permitem introdu- zir mecanismos de segurança adicionais ou mitigar problemas de privacidade em diferentes protocolos. Isto resulta na implementação de mecanismos de segurança sobre protocolos de descoberta inseguros, assim como na intro- dução de mecanismos de atribuiçao e resolução de nomes que se focam na protecçao da privacidade. O principal veículo para a implementação destas soluções é através de ser- viços e protocolos de rede de uso geral. No entanto, a aplicabilidade destas soluções extende-se também a outros tópicos de investigação que recorrem a mecanismos de resolução de nomes para implementar soluções de intero- perabilidade, nomedamente a Internet das Coisas (IoT) e redes centradas na informação (ICN).Programa Doutoral em Informátic