Suppose my smartphone has been compromised and there is malicious software running on it. You can assume that the malicious software has broken out of any sandboxes and is running as root.
If I'm on a phone call, can the malicious software change what I'm hearing? Can it modify the audio of the phone call? In other words, can it mount a man-in-the-middle attack on the audio channel of a phone call that I place from my smartphone or that I receive on my smart phone?
Also, can the malicious software eavesdrop on the phone call, i.e., can it record the audio of the entire call?
I realize this might be a little bit "science-fiction-y". Still, I'm interested in whether it is possible, even in principle. Or is there some fundamental barrier that would make it difficult or impossible for an attacker who has compromised the software on my smartphone to mess with my phone calls like this?