Stumbled onto this project today.
mDesktop 1.6beta3 has something called "OpenCandy" in it. (The OpenCandy license is listed in the mDesktop license agreement. Yes, I do read those.) This is essentially adware. It's detected by Microsoft Security Essentials as something bad, for one --
as of yesterday, at least.
"OpenCandy" is in a good quantity of free software you'll find on teh intarwebs. There's a partial list in the Wikipedia link I mention, below.
Is OpenCandy "malicious"? That's a matter of opinion. It's adware. If you consider ads to be malware, you're going to want to skip this version.
Further reading:
http://en.wikipedia.org/wiki/OpenCandy
http://www.opencandy.com/faqs/
Simple solution: use mDesktop 1.5. Hey, if you look at the installer size, 1.6 is 714k and 1.5 is 282k.