Are there any known ways to gain access to firmware (bios/EFI) and permanently change the audio in a way that would effect the quality (Clarity, Volume, Frequency Range, Dynamic Range). For instance could an attacker gain access to my I/O and alter it without necessarily needing to flash my computer?
The reason I ask is I believe my friends and I have the pleasure of being infected with a weird malware that does just that. Our systems have became slightly slower, and the most noticeable symptom is the audio quality changes through out the day. I completely cleared a hard drive with Windows on it and installed Linux. The audio stopped changing, however the audio quality is now permanently horrific. The malware has spread among the people I work with. One way I know it spreads is by USB because shortly after transferring files, the computer started to show symptoms. I also believe it spreads wirelessly somehow (but not a 100%) because a fresh computer that was not infected and only was used for emails got infected in the same fecanity as the other computers. On the infected computers I hear clicks throughout the day, even when no audio is playing.