From Dan Ilett’s Evil twin could pose Wi-Fi threat (CNET News.com: 21 January 2005):
Researchers at Cranfield University are warning that “evil twin” hot spots, networks set up by hackers to resemble legitimate Wi-Fi hot spots, present the latest security threat to Web users.
Attackers interfere with a connection to the legitimate network by sending a stronger signal from a base station close to the wireless client, turning the fake access point into a so-called evil twin.