Friday, January 19, 2007
The next time you're at an airport looking for a wireless hot spot, and you see one called "Free Wi-Fi" or a similar name, beware -- you may end up being victimized by the latest hot-spot scam hitting airports across the country.
You could end up being the target of a "man in the middle" attack, in which a hacker is able to steal the information you send over the Internet, including usernames and passwords. And you could also have your files and identity stolen, end up with a spyware-infested PC and have your PC turned into a spam-spewing zombie. The attack could even leave your laptop open to hackers every time you turn it on, by allowing anyone to connect to it without your knowledge.
If you're a Windows Vista user, you're especially susceptible to this attack because of the difficulty in identifying it when using Vista. In this article, you'll learn how the attack works and how to keep yourself safe from it if you use Windows XP or Vista.
How the attack works
First, let's take a look at how the attack works. You go to an airport or other hot spot and fire up your PC, hoping to find a free hot spot. You see one that calls itself "Free Wi-Fi" or a similar name. You connect. Bingo -- you've been had!
The problem is that it's not really a hot spot. Instead, it's an ad hoc, peer-to-peer network, possibly set up as a trap by someone with a laptop nearby. You can use the Internet, because the attacker has set up his PC to let you browse the Internet via his connection. But because you're using his connection, all your traffic goes through his PC, so he can see everything you do online, including all the usernames and passwords you enter for financial and other Web sites.
In addition, because you've directly connected to the attack PC on a peer-to-peer basis, if you've set up your PC to allow file sharing, the attacker can have complete run of your PC, stealing files and data and planting malware on it.
You can't actually see any of this happening, so you'd be none the wiser. The hacker steals what he wants to or plants malware, such as zombie software, then leaves, and you have no way of tracking him down.
All that is bad enough, but it might not be the end of the attack. Depending on how you've connected to that ad hoc network, the next time you turn on your PC, it may automatically broadcast the new "Free Wi-Fi" network ID to the world, and anyone nearby can connect to it in ad hoc peer-to-peer mode without your knowledge -- and can do damage if you've allowed file sharing.
While some of these ad hoc networks advertising themselves as available for connection may be attributable to Windows behavior that the PC's user is unaware of, wireless ad hoc attacks may be more common that you think. Security company Authentium Inc. has found dozens of ad hoc networks in Atlanta's airport, New York's LaGuardia, the West Palm Beach, Fla., airport and Chicago's O'Hare. Internet users have reported finding them at LAX airport in Los Angeles.
Authentium did an in-depth survey of the ad hoc networks found at O'Hare, visiting on three different occasions. It found more than 20 ad hoc networks each time, with 80% of them advertising free Wi-Fi access. The company also found that many of the networks were displaying fake or misleading MAC addresses, a clear sign that they were bent on mischief.
"You connect to one of these networks at your own peril," says Corey O'Donnell, vice president of marketing at Authentium. "And you would have no way of tracking down how you were attacked, because you would have thought you were at an ordinary hot spot connection. Enterprises are also at risk, because if someone uses a corporate laptop to connect to one of these networks and gets infected, when he plugs back in to the enterprise network, the whole network is put at risk."
How to protect yourself in Windows XP
Protecting yourself against these kinds of attacks is quite easy: Never connect to an ad hoc network unless someone you know has set one up and specifically asks you to connect. So no matter where you are, if you see an ad hoc network, don't connect, no matter the name of the network.
Be aware that someone can name an ad hoc network anything they want, so they can even duplicate the name of a legitimate network. For example, if you're at an airport, and the name of the airport's free hot spot is AirNet, someone can set up an ad hoc network with that exact same name. You'd see two networks called AirNet, one being the legitimate one and the other being the scam ad hoc network.
In Windows XP, it's easy to differentiate between an ad hoc network and a normal Wi-Fi network (Microsoft calls connecting to a hot spot or access point being in "infrastructure mode"). In Windows XP, in order to connect to a wireless network, you click the wireless network icon in the system tray, and the "Choose a wireless network" connection screen appears. You'll see a list of all nearby wireless networks.
As you can see in the nearby figure, each network includes a name and a description. Look at the description. If it's an ad hoc network, it will be called a "computer-to-computer" network; normal wireless networks are simply called wireless networks. In the figure, the "Free Airport WiFi" network is an ad hoc network. You should stay away from it
|Windows XP displays the details of every nearby
wireless network, including whether it's an ad hoc network. In this
screen, the Free Airport WiFi network is an ad hoc network.|
(Click image to see larger view.)
There are other steps you can take to make sure you don't accidentally connect to an ad hoc network created by a scamster. For example, you can make sure that XP never connects to an ad hoc network. To do it:
Note: If a wireless icon isn't displayed in your System Tray, you can get to your wireless connection by clicking on Start, going to Settings, then Control Panel and then Network Connections. Then double-click on the wireless connection icon to bring up the panel that displays the "Change advanced settings" link. An alternate path on some systems might be Start --> Control Panel --> Network and Internet Connections --> Network Connections, then double-click on the wireless network connection icon.
|This screen lets you tell your PC never to connect to ad hoc networks.|
When you're at the "Advanced" screen, you should also make sure the box next
to "Automatically connect to non-preferred networks" is not checked. If that box
is checked, your PC will connect to any nearby wireless network, without
alerting you, which is a serious security risk.
It's also a good idea when you're on the Wireless Networks tab to look at all the wireless networks listed in the Preferred networks area (shown in the nearby figure). These are networks that at one time or another you've connected to. Highlight any that you are not absolutely sure are secure, then click Remove. That way, your PC won't attempt to connect to them.
|Remove any unfamiliar networks from the Preferred
(Click image to see larger view.)
There's more you should do as well. You should also configure your remaining preferred networks so that you don't connect to them automatically. Why do that? Let's say your home network uses the default name it shipped with --- for example, Linksys for a Linksys network. A scamster can create an ad hoc network called Linksys, and then anyone nearby who has Linksys listed as a preferred network will automatically connect to that ad hoc network.
So in the Preferred networks area, highlight each network, select Properties, then click the connection tab, shown in the nearby figure. Uncheck the box next to "Connect when this network is within range" and keep clicking OK until the dialog boxes close.
|Make sure to tell your PC not to make any
automatic connections to wireless networks.|
(Click image to see larger view.)
Keeping safe in Windows Vista
Microsoft spent a considerable amount of effort making Windows Vista more secure than Windows XP, but when it comes to wireless networking, you're more at risk in Windows Vista from an ad hoc attack than you were in Windows XP. That's because in Windows Vista, it's not as easy to distinguish an ad hoc network from a normal Wi-Fi network as it is in Windows XP. However, once you know the trick, it's easy to do.
In Windows Vista, you connect to a wireless network by first clicking the network icon in the System Tray, then selecting "Connect or disconnect." The "Connect to a Network" screen shows up, with a list of nearby wireless networks. You see the name of each and whether the network is encrypted or not; to get more details about any, hover your mouse over it, as shown in the nearby figure. But those details don't include whether the network is a true hot spot or an ad hoc network.
Before you connect to a new wireless network, the only way to tell the difference between an ad hoc network and one in infrastructure mode is to look at the network icon next to it on the "Connect to a Network" screen. As you can see in the nearby figure, the icon for a normal Wi-Fi network is one computer, while the icon for an ad hoc network instead is several computers. That's it; there's no other way to distinguish between the two.
|The only way to distinguish between ad hoc and
normal wireless hot spots is to look at the network icon on this screen.
An ad hoc network's icon is made up of several PCs; a normal network is
made up of one PC.|
(Click image to see larger view.)
Here's another oddity: If you right-click the list of available networks, on the menu that appears, some of them have a Properties menu item and others don't. Only those networks that you've previously visited and saved to your network list will have the Properties menu item. If you choose Properties, select the Connection tab and look next to Network Type, you'll see whether it's an ad hoc network or an access point (a normal hot spot).
But if you haven't yet connected to the network (or if you have connected previously but haven't saved it), it won't have the Properties menu item. So you can't use that method of distinguishing between ad hoc and normal Wi-Fi networks when you're looking for a hot spot on the road.
Other steps you can take
There are other steps you can take to keep yourself safe, including turning off file sharing and running your company's VPN when at a hot spot. You can also pay to use a VPN such as HotSpotVPN. For details and many other tips for keeping yourself safe, see "How to protect yourself at wireless hot spots".
In addition, Authentium is working with financial institutions to create a product called VirtualATM, which will help protect you when you connect to a financial institution. It's expected to be released later this year.