During our recent power outage (caused by this weekend's freak snowstorm), I took refuge at a public library in a town some miles away. That library did have power and wi-fi Internet connections. Most important of all, the building also had heat. I spent several hours there yesterday, building the Plus Edition email newsletter and then sending it by email to each subscriber.
While at the library, I found huge security issues. Actually, I have seen them before when in hotel rooms or in public waiting areas at airports. However, I saw more security issues within a few minutes yesterday than I had ever seen before at any one time. About 30 or 40 people were in the library at the time, most of them using laptop computers. I believe that most of them, like me, were there to use the wi-fi Internet connection. In fact, there were so many of us using the single wi-fi router that it kept locking up and crashing every half hour or so.
In my Mac, I opened the Airport icon (Airport is the Macintosh term for wi-fi networking) and looked at available systems. About two dozen computers were listed. Some of the computers were listed by the names of the owners while others had some cryptic names, such as: BF354SA. This is not unusual for any place where a lot of laptop computers are in use in a small area. In any Windows or Macintosh computer, you can normally see the names of nearby computers on the same network you are using.
Now for the fun part:
I started clicking on computer names at random. On about half the computers in the network, I was able to gain access to the computer's contents without being asked for a user name or password! Yes, these people have configured file sharing on their laptop computers. The use of user names and passwords is optional in today's operating systems although I will suggest that it should be mandatory. Setting up file or printer sharing without requiring user names and highly-secure passwords is a security problem by itself. Then taking that computer to a public area where dozens of people will have access to your most important files strikes me as high risk.
I admit that I poked around in other people's computers for a bit. On a couple of computers I accessed, I could see and copy anything in the Documents folders and other folders as well. I even copied a couple of MP3 music files from one person's iTunes folder. Another person had a folder named "QuickBooks" but I decided to not click on it. There are some things I don't want to know!
In short, these people were making their sensitive files available to everyone. That's sort of like leaving the front door unlocked in your home when you leave the premises. You don't know who will access your things.
I checked my own laptop's configuration. I had file sharing turned off, so no one can access my files. Admittedly, when at home I do use file sharing occasionally to copy files from the desktop to the laptop or vice versa. However, I only turn file sharing on for the few minutes I actually need it, and then a user name and password are required to gain access from any other computer on the network. When finished, I always turn file sharing off in the laptop computer.
Let me ask you some questions: Do you have file sharing or printer sharing turned on? If so, are a user name and password required to gain access to your files? Not only are you at risk while at the library, but also when using your computer at the airport, in a hotel room, on the commuter train, or even at home if you have neighbors within wi-fi range.
It is bad enough to enable wide open file sharing without user names and passwords on a desktop computer where your next-door-neighbors might be able to access your files by wi-fi. However, it is far worse when you take a laptop computer to a library, courthouse, hotel room, or airport waiting lounge where many more laptop computers are in use, greatly increasing the odds that someone will discover that your computer's "front door is unlocked."
Again, file sharing is not the culprit. You can turn on file sharing and still maintain security by requiring user names and lengthy passwords. The security problems arise from turning on file sharing and then not requiring user names and passwords for access.
For Windows XP users, instructions may be found on Microsoft's support site at http://support.microsoft.com/kb/307874
For Windows Vista users, instructions may be found on Microsoft's support site at http://technet.microsoft.com/en-us/library/bb727037.aspx
For Windows 7 users, instructions may be found on Microsoft's support site at http://social.technet.microsoft.com/Forums/en/w7itprosecurity/thread/9a87b20f-15a4-4eff-b678-f228166f6d0a
For Macintosh users, go to System Preferences, click on Sharing, and make sure all the boxes are unchecked. You can also watch a video on Apple's web site at http://www.apple.com/findouthow/mac/#wirelessmore
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