What is the ruling on using programs and operating systems for something forbidden?

Selling and producing programs and systems used for both lawful (halal) and unlawful (haram) purposes is permissible, unless it is known or highly probable that the buyer will use them for unlawful purposes. In such a case, it is not permissible to sell them to him, because that would be aiding in sin. Allah Almighty says: "And do not cooperate in sin and aggression," and the means to the forbidden are forbidden.