Wi-Fi Alliance: What is an "Evil Twin?"

What is an “Evil Twin”?

An Evil Twin, sometimes referred to as Wiphishing, is a potential security threat to users
of Wi-Fi, predominantly in public hotspots. A hacker sets up what is called a "rogue
access point" which mimics the characteristics of the network to which users expect to
connect. Users unknowingly connect to the rogue access point and the hacker's
network instead of the intended network.

The Evil Twin hijacks data, such as passwords, account information, credit card
information, etc., and then connects the user to the Internet as intended. A sophisticated
evil twin can even control what Web site appears when the Internet is accessed, often
mimicking the intended starting Web site, for the purposes of capturing the user's private
information.

To date, there have been no reported large-scale incidences of Evil Twin attacks, but
most network administrators have been aware of this theoretical threat for some years.
Recent media coverage of Evil Twin threats has directed consumer attention to the
matter, making users concerned about the problem and how they can protect
themselves.

The Wi-Fi Alliance recommends that users of wireless networks exercise the same level
of caution they've learned to use to avoid scams in the wired world. End users should
change their passwords regularly, not respond to questionable e-mails, and look for
secure connections. As Wi-Fi continues to grow in reach and popularity, consumers
need to make some new simple security precautions a habit, like connecting through a
provider that uses encryption with a list of trusted hotspots, using a VPN, and always
enabling security within a home network. Also, users should make it a point to look for
products that are Wi-Fi CERTIFIED for or WPA2 security.

via wi-fi.org