Stegozoa

Abstract

Several totalitarian states around the world deploy sophisticated censorship apparatuses to prevent citizens from freely accessing the Internet. To counter these restrictions, some censorship-circumven-tion tools establish covert channels through the media streams of popular conferencing applications. A recent tool named Protozoa allows for establishing high-performing, peer-to-peer covert channels over WebRTC media streams. However, Protozoa is vulnerable to potential man-in-the-middle attacks. This may occur in cases where WebRTC applications rely on WebRTC gateways to mediate users' connections. In such cases, an adversary that controls the WebRTC gateway can inspect the content of the media streams and trivially detect the transmission of covert payload.