Cheating in video games is a critical financial matter for game developers. With games now integrating physical objects through NFC, new cheating techniques have emerged, including characteristic boosting of the objects, duplication of objects and introduction of new unauthorized objects. In this paper, we address this problem for games based on active NFC objects. Having active objects in a game allows for new possibilities of interaction yet to be seen, including offline interactions between objects outside of the game. We identify four top security requirements for these games to remain resistant to cheating activities. This analysis is original as it introduces a new model with active NFC objects. Our system is composed of a server, a device (computer, console or smartphone) equipped with an NFC reader, and NFC objects. We perform a risk analysis to identify the weak points of this base system. We list several realistic attacks exploiting the system's weaknesses. Finally, to address them, we design four cost effective security requirements