Sound Covert: A Fast and Silent Communication Channel through the Audio Buffer
Ofir Shwartz, Yitzhak Birk · 2017
We present Sound Covert, a novel technique using the machine's audio buffer to secretly (and silently) communicate between applications. Sound Covert can achieve more than 2.6Mbps, four orders of magnitude faster than previously published covert channels. Sound Covert can be used for bidirectional communication between malicious applications anywhere within a given VM (including across users and sand boxes), as well as for sending information from within a VM to an application running on the host OS of the same physical machine. It can also be used for sending information from a compromised external web page to a local malicious application through an innocent, unaltered web browser running in the target application's VM. Similarly, Sound Covert enables a malicious application in a VM that also runs a web server to send data to a malicious partner application running on any machine (or VM) that has a web browser.