My work computer is missing two keys and has been since they signed it out to me.

I'm betting they don't notice if I file down the corners. Hell they probably wouldn't notice if I just cut the corners off with a fret saw. But God forbid I try to install an ad blocker or use Firefox.

> Doing this to a work computer seem a bit questionable from the ethical standpoint.

"Ethical standpoint" seems like the wrong choice of words. I think you mean "equipment ownership standpoint.". Ethical implies a set of values, vs contractual terms of equipment use.

You can't be unethical to your employer, only to people like your coworkers and customers, or other living beings that your business activity impacts.