What is an idiom or saying for "seeking gain in a way harmful to others"

Question

In Arabic, we have a phrase that literally translates as:

To seek gain (make a living/money or profit) on my nape

And we use it when we want to say someon's way of seeking gain is harmful to us as if that person was walking on our nape. For example, when you work for a company and you are caught directing the company's customers to another company that you have links with.

I could imagine that such a phrase does exist with the word "ass". It is close to "mooch off of someone" but it is not quite the same. Another example is when a vendor decides to do business in front of a shop causing disturbance at the shop's entrance. The shop owner may walk up to him and say, I imagine, "are you trying to ... off of my ass?".

Answer 1

Although not an idiom, the very definition of the verb to exploit fits your description uncannily precisely. This is how the Google dictionary defines it:

Make use of a situation in a way considered unfair.

Underhand or benefit unfairly from the work of someone, typically by overworking or underpaying them.

However, the verb to use, believe it or not, could actually be even a better option. Here are a couple of examples:

He was using the company's resources for his own personal gain.

I thought she loved me, but as it turned out she was using me for my money.