iOS URL Schemes: omg://

Have you ever clicked a phone number in Safari to get the phone app to call that store/car dealership/pizza place you were searching for? In iOS, this interaction between apps happens via URL schemes, which are available to Apple applications as well as third party applications. Everyone uses them without noticing they exist. They are the most flexible of the imperfect methods available right now. They are, however, a source of user input that should never be trusted as safe. In this presentation, we will look at real life examples of implementations of URL Schemes that could lead to issues such as destruction of data or help a malicious person identify an iOS user. We will also look at simple ways to improve URL Scheme security for users of your apps as well as how to find URL Scheme vulnerabilities, for the ones out there who would like to help out.