Align footer of a div, with footer of another div

Question

Good guys, I am doing a web project using bootstrap. I would like to know the following:

I have a div, where the amount of elements within it (inputs) is less than a second div, on its side (both with col-Md-6 inside a Row). The image below illustrates the situation.

What I would like to know is how I can align the left div with the right div footer, without having to fix the size of the Divs (as there may be a need to include more fields. The image below illustrates the expected result.

Detail: There is no custom CSS in these boxes, only using the Grids and bootstrap alignments.

Answer 1

I did as follows, half-manual but solved the problem. Who can complement the answer with a way to do via CSS thank you.

$('#box-left'). height($('#box-right').height());