I think you're asking about "How we can be assured that the software we are going to install is secure or not"?
If this is the question than you perform following things to ensure it:
1. Check about the detail of the software and its copyright T&C.
2. Try checking its official site, all genuine software have their official sites and they reveal all about them there.
3. If you're not sure about the software, try installing it in the safe mode option, and see if asking any permissions or not.
4. If you really want to go in depth you can read all the T&C of the software during the time of its installation.
5. Finally, the most important. If you're not sure about the software never install it in your Hard Drives, try using a external drive for this purpose.
Hope these things works for you! Let us know your feedback!