Mobile application developers define the terms of use for the applications they develop, which users may accept or declined during installation. Application developers on the one hand seek to gain access to as many user information as possible, while users on the other hand seem to lack awareness and comprehension of privacy policies. This allows application developers to store an enormous number of personal data, sometimes even irrelevant to the application’s function. It’s also common that users choose not to alter the default settings, even when such an option is provided. In combination, the above conditions jeopardize users’ rights to privacy. In this research, we examined the Viber application to demonstrate how effortless it is to discover the identity of unknown Viber users. We chose a pseudorandom sample of 2000 cellular telephone numbers and examined if we could reveal their personal information. We designed an empirical study that compares the reported behavior with the actual behavior of Viber’s users. The results of this study show that users’ anonymity and privacy is easily deprived and information is exposed to a knowledgeable seeker. We provide guidelines addressed to both mobile application users and developers to increase privacy awareness and prevent privacy violations.