Evil Twin is a term for a rogue Wi-Fi access point that appears to be a legitimate one offered on the premises, but actually has been set up by a hacker to eavesdrop on wireless communications among Internet surfers. This type of Evil Twin Attack may be used by a hacker to steal the passwords of unsuspecting users by either snooping the communication link or by phishing, which involves setting up a fraudulent Web site and luring people there. A rogue Wi-Fi connection can be set up on a laptop with a bit of simple programming and wireless card that acts as an access point. The access points are hard to trace, since they can suddenly be shut off, and are easy to build. A hacker can make their own wireless networks that appear to be legitimate by simply giving their access point a similar name to the Wi-Fi network on the premises. Since the hacker may be physically closer to the victim than the real access point, their signal will be stronger, potentially drawing more victims. The hacker's computer can be configured to pass the person through to the legitimate access point while monitoring the traffic of the victim, or it can simply say the system is temporarily unavailable after obtaining a user id and password. Several free programs available on the Internet can decode packets to reveal clear-text logins and passwords. Using an Evil Twin attack a hacker is able to harvest Web applications such as email that could send passwords in clear text. One way that Corporate users can protect themselves from an Evil Twin attack is by using VPN (virtual private network) when logging into company servers. They should not send sensitive information such as bank account information or corporate user ids and passwords over a wireless network. Hackers typically setup Evil twin attacks near free hotspots, such as airports, cafes, hotels or librarie.