Countermeasures to free software that secretly uses CPU time to mine cryptocurrencies

They say if you think there is a free lunch, you are the lunch. Free proxy software such as psiphon MAY be an example. The CPU monitor often goes right up with this, even when you are not downloading anything. This is in windows actually but similar things happen in linux with other freeware such as kproxy agent. It is not enough to run the software with a low priority, it still consumes power. How can we slow down the mining but hopefully not mess up the useful function?