Evil Twin Wi-Fi attack is an attack on the 802.11 IEEE standard. The attack poses a threat to wireless connections. Evil Twin Wi-Fi attack is one of the attacks which has been there for a long time. Once the Evil Twin Wi-Fi attack is performed this acts as a gateway to many other attacks such as DNS spoofing, SSL Strip, IP Spoofing, and many more attacks. Thus, preventing the attack is essential for privacy and data security. This paper will be going through in detail how the attack is performed and different measures to prevent the attack. The proposed algorithm sniffs for fake AP using the whitelist in all the channels, once an unauthorized AP is detected the user has an option to de-authenticate any user in the unauthorized network in case any clients do connect to it by accident also the algorithm will be checking if any de-authentication frame is being sent to any of the AP to know which of the AP is being compromised. The efficiency of proposed approach is verified by simulating and mitigating the evil-twin attack.