I<sup>2</sup>-diagnosability framework for detection of Advanced Stealth Man in the Middle attack in Wi-Fi networks
The diagnosability condition for a Discrete Event System (DES) model requires that there exists no failureindeterminate cycles in the DES diagnoser for all failure types. This stringent requirement of DES diagnosability condition renders many systems non-diagnosable. I-diagnosability framework provides a weaker notion of diagnosability than DES diagnosability by considering only those failures that are followed by certain observable event(s) known as indicator events. However, some systems are I-non-diagnosable even in the presence of an indicator event following the failure event. In this paper, we propose I2-diagnosability framework overcomes the shortcomings of the I-diagnosability framework. In I2-DES framework an empowering event ensures that the indicator event sensitizes the failure successfully. We have considered a practical example of Advanced Stealth Man in the Middle attack in Wi-Fi networks to demonstrate the effectiveness of the proposed I2-DES framework wherein the I-DES framework fails.