Hackers will try anything to gain access to your personal details and data in an attempt to profit from them. Any device attached to your PC should be viewed as a threat, and that now includes your speakers.
As Engadget reports, a team of researchers at Ben Gurion University in Israel created a proof-of-concept software hack that turns your computer speakers into a microphone. In so doing, a user is completely oblivious to the fact they are being listened to and possibly recorded. It also works with any headphones or earphones plugged into a PC.