As a network security consultant, I travel quite frequently. At times, it seems like the airport is my second home. I actually like to fly, it's a moment in time where no one can reach me by e-mail, or mobile phone.
It never fails that something interesting happens to me at the airport. I've even met some famous people during my travels. A few months ago, I ran into Frank Bielec, from the TLC show, Trading Spaces. But one of my favorite things to do at the airport is browse the wireless Ethernet waves. I'm never really surprised at what I find. I'm just glad I know more about wireless Ethernet than the average road warrior.
The Dangers Of Ad-Hoc Wireless Networking
Most people who have wireless Ethernet at home, or the office, connect to the wireless network by attaching to a wireless Access Point, or AP. This method of wireless networking is called "Infrastructure Mode". If you have a secure wireless network configured in "Infrastructure Mode" you are using MAC address filtering, some level of encryption, and have made some additional changes to your AP in order to prevent just anyone from using it or capturing data. For more information on configuring your "Infrastructure Mode" wireless network take a look at the "Wireless Network Security" page at Defending The Net.
However, for those who are not using "Infrastructure Mode", and are configured to communicate from machine to machine, or "Ad-Hoc", there are a few things you should be aware of.
A wireless Ad-Hoc network allows you to communicate with other wireless Ethernet systems without using a wireless access point. It's kind of a peer to peer configuration and it works rather well. The problem is, most people just set it up, and forget about it. At home, it's not a huge problem, but when your on the road, it could cause you a great deal of grief. The airport is probably the best place to find Ad-Hoc networks. Business men and women, delayed once again, power up their laptops and get to work completing the days tasks, or planning tomorrows agendas.
I can't tell you how many systems I find in the airport configured this way. Not just in the terminal, but on the plane. About three months ago, just after we reached cruising altitude and were allowed to use our "approved electronic devices", I found that the gentleman two seats up from me had a laptop configured as Ad-Hoc. He walked by me about ten minutes later and commented on how much he liked my laptop. I thanked him, and asked if his laptop was on, and configured to use wireless Ethernet, he said yes.
To make a long story short, I showed him that I could see his laptops wireless Ethernet and informed him of the danger. He asked me if I could access his hard drive, and I told him that it might be possible. He asked me to see if I could, so I obliged. After configuring my laptop to use the same IP address class as his, and typing "net use * hiscomputersIPAddressc$ "" /USER:administrator", I received a notice that the connection was successful and drive Z: was now mapped to his computer. I performed a directory listing of his hard drive and the guy almost had a heart attack!
After this, he moved up to the seat next to mine and we spent the next hour or so configuring his laptop securely, starting with securing his computers local administrator account. At one point during the configuration, he made the statement that I got real lucky because his local admin account did not have a password. My response to him was, I get lucky quite often.
Who Else Has Your Client List
Just think of the possibilities. What do you have to lose if someone is able to just peruse the files and data on your laptop? Do you maintain your customer list on your laptop (Do you want this in the hands of a competitor)? How about your personal finances (Identity theft ring a bell)? So many people I talk to initially say, "I really don't have anything of great importance on this system". Then they think a little bit and start rattling of things they never really thought about before. All of a sudden, they get concerned.
The fact is, whether it be "Infrastructure Mode", or "Ad-Hoc" wireless Ethernet communications, if not properly configured and secured, can pose a significant risk. There are thousands of articles on the Internet about the dangers of improperly configured wireless networks, yet the number of unsecured networks seems to be getting greater, not less.
Strength And Posture Does Reduce Your Risks
Keep in mind that your objective should be to reduce the chances that you will become a target for computer compromise. When I was growing up in South Philadelphia, I remember my father telling me that when you walk down the street, especially in the evening, to walk tall, and project a position of strength and authority. Why, because thugs typically pick out those who look like an easy target. The same thing goes for computer security. Reduce the risks of becoming a target buy configuring your system with a strong security policy.
When I perform security assessments, I create a list of potential targets, and potential methods of compromise. I then prioritize that list by which system, with a particular vulnerability, may be easiest to compromise. Those at the bottom of the list typically never come on my radar screen; the best scenario it to keep of the radar altogether.
Conclusion
If your are using wireless Ethernet, no matter what configuration, follow a few rules and keep yourself secure against most common types of compromise.
1. Above all, make sure all your user accounts have strong passwords, especially those that have administrative control over your system;
2. Configure your wireless network to use some sort of encryption. I know there is a lot of concern about the "crackability" of WEP, but if this is all you have to work with, and then use it. It is still helpful;
3. If possible, use MAC addresses filtering to restrict unwanted systems from attaching to your wireless network;
4. Make sure the firmware for your AP's and wireless Ethernet cards are up to date. These updates can be found on your card or AP's support site.
Remember, if you are compromised over your wireless network it can be near impossible to track down where the attack came from. Worse yet, think about how many systems become compromised, and no one ever knows it?
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