Your Code Is My Code: Exploiting a Common Weakness in OAuth 2.0 Implementations

Many millions of users routinely use their Google, Facebook and Microsoft accounts to log in to websites supporting OAuth 2.0-based single sign on. The security of OAuth 2.0 is therefore of critical importance, and it has been widely examined both in theory and in practice. In this paper we disclose a new class of practical attacks on OAuth 2.0 implementations, which we call Partial Redirection URI Manipulation Attacks. An attack of this type can be used by an attacker to gain a victim user’s OAuth 2.0 code (a token representing a right to access user data) without the user’s knowledge; this code can then be used to impersonate the user to the relevant relying party website. We examined 27 leading OAuth 2.0 identity providers, and found that 19 of them are vulnerable to these attacks

The Web SSO Standard OpenID Connect: In-Depth Formal Security Analysis and Security Guidelines

Web-based single sign-on (SSO) services such as Google Sign-In and Log In with Paypal are based on the OpenID Connect protocol. This protocol enables so-called relying parties to delegate user authentication to so-called identity providers. OpenID Connect is one of the newest and most widely deployed single sign-on protocols on the web. Despite its importance, it has not received much attention from security researchers so far, and in particular, has not undergone any rigorous security analysis. In this paper, we carry out the first in-depth security analysis of OpenID Connect. To this end, we use a comprehensive generic model of the web to develop a detailed formal model of OpenID Connect. Based on this model, we then precisely formalize and prove central security properties for OpenID Connect, including authentication, authorization, and session integrity properties. In our modeling of OpenID Connect, we employ security measures in order to avoid attacks on OpenID Connect that have been discovered previously and new attack variants that we document for the first time in this paper. Based on these security measures, we propose security guidelines for implementors of OpenID Connect. Our formal analysis demonstrates that these guidelines are in fact effective and sufficient.Comment: An abridged version appears in CSF 2017. Parts of this work extend the web model presented in arXiv:1411.7210, arXiv:1403.1866, arXiv:1508.01719, and arXiv:1601.0122

Do not trust me: Using malicious IdPs for analyzing and attacking Single Sign-On

Single Sign-On (SSO) systems simplify login procedures by using an an Identity Provider (IdP) to issue authentication tokens which can be consumed by Service Providers (SPs). Traditionally, IdPs are modeled as trusted third parties. This is reasonable for SSO systems like Kerberos, MS Passport and SAML, where each SP explicitely specifies which IdP he trusts. However, in open systems like OpenID and OpenID Connect, each user may set up his own IdP, and a discovery phase is added to the protocol flow. Thus it is easy for an attacker to set up its own IdP. In this paper we use a novel approach for analyzing SSO authentication schemes by introducing a malicious IdP. With this approach we evaluate one of the most popular and widely deployed SSO protocols - OpenID. We found four novel attack classes on OpenID, which were not covered by previous research, and show their applicability to real-life implementations. As a result, we were able to compromise 11 out of 16 existing OpenID implementations like Sourceforge, Drupal and ownCloud. We automated discovery of these attacks in a open source tool OpenID Attacker, which additionally allows fine-granular testing of all parameters in OpenID implementations. Our research helps to better understand the message flow in the OpenID protocol, trust assumptions in the different components of the system, and implementation issues in OpenID components. It is applicable to other SSO systems like OpenID Connect and SAML. All OpenID implementations have been informed about their vulnerabilities and we supported them in fixing the issues

WPSE: Fortifying Web Protocols via Browser-Side Security Monitoring

We present WPSE, a browser-side security monitor for web protocols designed to ensure compliance with the intended protocol flow, as well as confidentiality and integrity properties of messages. We formally prove that WPSE is expressive enough to protect web applications from a wide range of protocol implementation bugs and web attacks. We discuss concrete examples of attacks which can be prevented by WPSE on OAuth 2.0 and SAML 2.0, including a novel attack on the Google implementation of SAML 2.0 which we discovered by formalizing the protocol specification in WPSE. Moreover, we use WPSE to carry out an extensive experimental evaluation of OAuth 2.0 in the wild. Out of 90 tested websites, we identify security flaws in 55 websites (61.1%), including new critical vulnerabilities introduced by tracking libraries such as Facebook Pixel, all of which fixable by WPSE. Finally, we show that WPSE works flawlessly on 83 websites (92.2%), with the 7 compatibility issues being caused by custom implementations deviating from the OAuth 2.0 specification, one of which introducing a critical vulnerability

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

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