Indeed. And there are a ton of comments here saying it's OK because "she went through the standard approval process, which requires two co-workers to greenlight changes."

But that doesn't mean it was OK. It just means the co-workers might have greenlit it without taking a close look, or were misled as to what they were approving, or that they were approving it because the code was correct technically, and approval isn't about judging the code's product purpose.

If this tool was NOT meant to be used as the equivalent of "posters on the wall" and she modified it, regardless of co-worker code approval, it DOES seem to be an abuse of privileges.

If her manager had given her the OK, then she's in the right. Otherwise, I have a hard time seeing how this isn't abuse of one's position.