Airport authorities around the country are warning flyers about a new security threat at airports: fake wireless networks that can steal users' information once travelers log on through their laptops.

Airport authorities around the country are warning flyers about a new security threat at airports: fake wireless networks that can steal users' information once travelers log on through their laptops.


The networks, designed by hackers to look like the wireless service that many airports provide, have been found at airports in Los Angeles and Atlanta, New York LaGuardia and Chicago O'Hare. In Chicago, a survey found as many as 20 different networks advertising free wireless at once, according to a press release from the Better Business Bureau in Natick.


Logan International Airport, however, so far appears to have escaped the networks, said Phil Orlandella, director of media relations at the airport.


``We do monitor the entire system and we have found no problem that we're aware of,'' Orlandella said.


Like most major airports, Logan provides wireless Internet access in every terminal.


In the case of the fake operations, once a user connects to the network - often named ``Free Wi-Fi,'' or bearing the same name as the airport's wireless service - the network administrator can steal keystroke information, such as usernames and passwords, and sometimes has access to documents on the user's computer as well.


The process is made possible by a feature on Windows and Macintosh computers called computer-to-computer network sharing, or ad-hoc networking. To set up an ad-hoc network, no wireless router is needed; instead, the hacker setting up the network is able to share his or her Internet connection directly with a small number of users.


The network then appears as available alongside legitimate Wi-Fi sources.


``It definitely seems like there are many major airports that have these proxy networks set up that look like they're for the purpose of stealing information,'' said Alison Preszler, a spokesman at the Council of Better Business Bureaus, headquartered in Virginia.


``This isn't something that I know of as exploding right now, but it's something that travelers need to be aware of,'' she said.


Unlike other forms of hacking, setting up an ad-hoc network can be very simple. And as wireless networks become more popular, computer users often find themselves with an increasing number of networks to choose from as more cities, restaurants and airports become equipped with hotspots. Hackers then have a far easier time stealing information.


``It's quite easy to do. My feeling is it has to do with awareness. With enough education and media coverage, people will see that this is a big issue,'' said Guevara Noubir, an associate professor of computer science at Northeastern University.


``It's true that there are so many access points. We can see that almost anywhere you go in Boston... there are a multitude available. But if the user is aware of what he's doing, he can protect his information,'' he said.


In the United States, 300 municipalities are either already operating or are planning Wi-Fi networks, according to the Los Angeles Times.