What is the ruling on my husband's work in a company that deals with banks and insurance companies, where he provides them with programs and devices for information security?

There is no objection to working in website security, but it is forbidden to provide these services or any other services to usurious banks or commercial insurance companies, because they are institutions based on what is unlawful. This is considered cooperation in sin and aggression, which Allah Almighty has forbidden in His saying: "And do not cooperate in sin and aggression." Furthermore, the noble Hadith: "Allah has cursed the one who consumes Riba, the one who feeds it, its scribe, and its two witnesses," and he said: "They are all equal," indicates the prohibition of assisting in falsehood. Therefore, if the husband's work is limited to providing services to Islamic banks or cooperative insurance companies, there is no objection to that, but he must refrain from providing services to usurious institutions.