What is the ruling on an administrative employee's work in a company that sells cigarettes, and does it differ from working in banks?

If the company deals exclusively in selling cigarettes, then working for it is forbidden (haram) because it constitutes aiding in sin. There is no difference between it and a usurious bank in terms of aiding in disobedience, even though usury is a greater sin. However, if the company has other permissible activities, then there is no objection to working for it, provided one engages only in the lawful area.