The aim of the present invention is to provide a method to detect misbehavior use of the IEEE 802.11 standard without modifying the standard itself. This aim is reached according to a method for detecting misbehavior in a contention based communication network, this method comprising the steps of: recording at least some of invalid frames with their respective station identification issued by the stations accessing an Access Point, recording at least some of valid frames with their respective station identification issued by the stations accessing the Access Point, determining, for each station, a scrambled ratio based on the number of invalid frames and the number of valid frames, detecting a misbehavior station based on a station which has a substantially lower ratio than the other stations.