Is selling and buying remote computer control software (which may be used for hacking) permissible, and is it permissible for a programmer to sell a program that allows the buyer to use it for hacking or for overt control?

If the prevalent use of a device hacking program is for unlawful purposes, such as espionage and harm, then its sale is absolutely impermissible. However, if that is not the case, then its sale is prohibited to anyone known or believed to be using it for ill purposes, but it is permissible to sell it to someone who will benefit from it for lawful purposes.