Is money earned from securing places for students in public universities for a fee—knowing that these places are not among those allocated in the special competition for foreign students—considered illicit gain?

If the seats are a free grant and offices obtain them through illicit means such as bribery, then working with them is impermissible, as it involves assisting in something forbidden. However, if the university administration officially sells these seats or grants them to specific entities that have the right to dispose of them, then there is no objection to that work.