That's what I do, on the stove top surface.
I guess you could put a cookie sheet under it on the counter to feel safer.

But...my 2 crockpots are new, and they stand on little legs. They don't seem to get the under surface too hot. -Are you sure your pot isn't getting too old or burnt out coils or something? No fire hazards I hope?

I have a friend who uses an ancient crockpot from the 70's she got at a garage sale- it kind of gives me the creeps, thinking it might do something dangerous.
I worry.