We all know about the unfortunate (to say the least) decision of Autodesk to abandon perpetual licenses of single products and sell only monthly or annual subscriptions.

I''ve seen though online stores in my country selling perpetual (at least so they say) licenses or older versions of AutoCAD, say AutoCAD 2013 LT.

I'm wondering if this is:
1. Possible
2. Legal

It sure is tempting, but I'm wondering if it's some kind of scum or something...