Itunes auto-sharing

So, I was remoting into a computer at work to allow our sales guy access to Itunes so he could upload photos from an Iphone.  He opens the Itunes and I see all the songs I have stored on my own workstation.  How do I stop this type of auto-sharing?  It seems like Itunes went through my network, found available music, and gave this sales guy the ability to upload them into his own laptop!  What the heck is that?
Movie Stars

Solution: Itunes auto-sharing