Methods and arrangements for securing a software defined network. One or more control messages are intercepted. Information is extracted from the one or more control messages to create a global network state model, and there is determined, from the extracted information, presence of at least one prospective modification to the global network state model. Thereupon, a determination is made as to whether the at least one prospective modification presents a threat to security of the software defined network. Other variants and embodiments are broadly contemplated herein.