What is the ruling on direct advertising contracts with entities that display prohibited content (such as images of unveiled women) when their ads are clicked, given the difficulty of monitoring these sites?

The basic principle is that it is permissible to advertise permissible things on the internet and elsewhere. However, it is not permissible to advertise or promote what is forbidden or what includes something forbidden, due to the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." Therefore, it is not permissible to advertise cars if the advertisement includes pictures of unveiled women, and the advertiser knows this or predominantly believes it to be the case, whether the contract was made directly or through an intermediary. This is because the viewer will see unveiled women, which is not permissible, due to the Almighty's saying: "Indeed, the hearing, the sight and the heart - all of those will be questioned."