a computer with internet connection .
however most " secrative organisations us a private access network " . you would want some programming experiance and knowledge of how networks work . in other words yes you would need knowledge of how these things work.
however hacking is illegal and even a pathetic none productive effort can land you in serious trouble so it is ill adviced in the first place as all computer connections leave a record which would lead the recipiant of such an attack streight to you " if they know how to " and in this case i am sure they do or know a man that can.