The ultrasonic frequency band represents a novel and so far hardly used channel for the communication between different devices, such as mobile phones, computers, TVs, and personal assistants like Google Chromecast. Ultrasonic communication is a promising technology since it requires only a standard loudspeaker and a microphone (as built into our phones) for communication. While offering a number of opportunities for innovative services (e.g. in the domain of Internet of Things), the technology, however, also bears a number risks, such as being exploited as a covert channel. Companies like Silverpush, for example, employed ultrasonic data exchange to track users across devices and to collect information about their behavoir without their knowledge. Furthermore, the acoustic channel can be used to exfiltrate information from IT infrastructures and to de-anomymize users. In my talk I will present the novel technology of ultrasonic communication, show how it works and which risks and chances are linked to it. Additionally, I will present the project "SoniControl" which aims at the development of an ultrasonic firewall to protect the privacy of users as well as the project "SoniTalk" which aims at developing a safe and privacy-oriented protocol for ultrasonic communication.