Dubbed Tamper-evident pairing or TEP [PDF], the technique is based on understanding how wireless messages are manipulated in a MitM attack, then detecting and, in some cases, blocking such manipulation. The researchers said TEP could have detected the attack reported at the DEFCON conference earlier this month in Las Vegas.
In all cases, the attack consists of manipulating wireless messages. The researchers claim to have identified these manipulation techniques and can be detected when they are being used.
TEP was devised by a group of MIT researchers: Shyamnath Gollakota, Ahmed Nabil, Zeldovich Nickolaik and Dina Katabi. His research paper, "Secure in-band wireless pairing," was presented at the recent USENIX Security symposium at MIT and you can see the research along the line.
Source: Networkworld, MIT [PDF]

