Is it permissible to benefit from proprietary software programs belonging to a company that has closed down, and to sell them after modifying them, knowing that the company's owners might not approve of this?

Contemporary scholars have differed on the issue of copyright and printing rights for books, tapes, and laser discs, holding three opinions on the matter: absolute prohibition unless the right belongs to a belligerent infidel, absolute permissibility, and permissibility for personal use only, not commercial use.

Accordingly, if the rights to the programs are reserved for the company, then it is not permissible to copy and sell them except with their permission. Modifications to the program do not change the ruling because its origin belongs to the company.