Disclosed herein is a method for displaying information about the use of a hack tool in the online game. When a game IDentification (ID) is input, a client system accesses a security server, and requests and receives the number of times that one or more hack tools have been used for the game ID. The client system provides the game ID and the number of times that hack tools have been used to a game server so that the number of times that hack tools have been used is shared by one or more gamers who participate in the game provided by the game server. When the client system detects the use of a hack tool, the client system increases the number of times that hack tools have been used for the game ID by 1, and provides the number of times that hack tools have been used to the security server.