Attack Patterns for Black-Box Security Testing of Multi-Party Web Applications

The advent of Software-as-a-Service (SaaS) has led to the development of multi-party web applications (MPWAs). MPWAs rely on core trusted third-party systems (e.g., payment servers, identity providers) and protocols such as Cashier-as-aService (CaaS), Single Sign-On (SSO) to deliver business services to users. Motivated by the large number of attacks discovered against MPWAs and by the lack of a single general-purpose application-agnostic technique to support their discovery, we propose an automatic technique based on attack patterns for black-box, security testing of MPWAs. Our approach stems from the observation that attacks against popular MPWAs share a number of similarities, even if the underlying protocols and services are different. In this paper, we target six different replay attacks, a login CSRF attack and a persistent XSS attack. Firstly, we propose a methodology in which security experts can create attack patterns from known attacks. Secondly, we present a security testing framework that leverages attack patterns to automatically generate test cases for testing the security of MPWAs. We implemented our ideas on top of OWASP ZAP (a popular, open-source penetration testing tool), created seven attack patterns that correspond to thirteen prominent attacks from the literature and discovered twenty one previously unknown vulnerabilities in prominent MPWAs (e.g., twitter.com, developer.linkedin.com, pinterest.com), including MPWAs that do not belong to SSO and CaaS families.