WPA (Wi-Fi Protected Access) Enterprise is the de facto standard for safeguarding enterprise-level wireless networks. It relies on Transport Layer Security (TLS) to establish a secure tunnel during its authentication process, and thus the notoriously error-prone certificate validation may haunt it. Incorrect validation may lead to the SSL/TLS man-in-the-middle attack, or the evil twin attack in the context of wireless networking, where the supplicant connects and unwittingly sends authentication credentials to a fake access point.