To dream that you are attacking someone implies that you are harboring deep feelings of anger and rage, which may ultimately bring physical pain or injury to someone else. You may hold the belief that someone has committed an immoral or sinful act against you. It is more beneficial to release these emotions in your dream rather than act them out in your waking life.
To dream that you are being attacked indicates that someone is criticizing your integrity, and you feel that you must stand up and preserve your good reputation. Some issue in your life is overwhelming you and you feel powerless to stop it. Perhaps you are being challenged with a very extreme and drastic alteration and you are being forced to make a hard decision.
To dream that you are being attacked by an animal indicates that you must guard against someone in your life that may intend to harm you. You should pay careful attention to the attributes that this animal may share with this particular person. Review the people you associate with and see if anyone shares these features.
To dream that you are killing an attacking animal indicates that an unfamiliar person will commit an act that prevents your injury or death.