Does insulting and cursing others by mentioning their mothers and sisters in chat rooms constitute slandering chaste women (Qadhf al-Muhsanat)? What is its ruling?

Qadhf (slanderous accusation of unchastity) is accusing someone of an abomination while they are innocent of it. If the insult does not include this meaning, then it is not considered qadhf. It is forbidden for a Muslim to insult his Muslim brother with any type of insult, or to insult his mother or sister. Internet users should utilize it for good, for inviting people to Allah, enjoining what is right, and forbidding what is wrong.