Technical solutions are described for preventing unauthorized transmission of data by a communication apparatus. An example computer-implemented method includes monitoring a data transmission request from an application being executed by the communication apparatus. The data transmission request is associated with transmission data. The method further includes securing the transmission data, where the securing includes identifying a content of a predetermined type in the transmission data, and generating secured transmission data. The secured transmission data includes a corresponding modified version of the content of the predetermined type. The computer-implemented method also includes transmitting the secured transmission data in response to the data transmission request.