David Petty

The same-origin policy remains one of the most important security mechanisms of the web, protecting servers from malicious pages interacting with their APIs through cross-site requests. However, the subtle details of the policy can be overlooked, so our talk aims to show how limitations in the application of the same-origin policy can undermine security. We explain in depth how the same-origin policy works and how it can be bypassed to exploit cross-site vulnerabilities, including examples of Java, Flash, Silverlight, and Cross-Origin Resource Sharing (CORS) misconfigurations. As the same-origin policy and cross-site request forgery (CSRF) are inherently connected, we will also show both simple and complex cross-site request forgery attacks and how CSRF functions within the context of the same-origin policy. This will include classic CSRF attacks that work within the confines of the same-origin policy and more complicated attacks that utilize server misconfigurations to bypass the same-origin restrictions altogether.

David is an Associate Security Analyst at Independent Security Evaluators (ISE), a security consulting company in Baltimore, MD. He has recently graduated from Northwestern University with a B.S. in Computer Science, and discovered his interest in security while working for ISE during college. He specializes in breaking web and mobile applications, reverse engineering, and digital forensics, and uses these skills to conduct custom security assessments of software products.

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