Question : Problem: Is my Airport Extreme being hacked?

Hi all,

I am running an Airport Extreme modem that supports two Macs and a PC.  I was having some trouble getting it working properly, but then a very smart tech at the Apple Genius Bar in SoHo, New York, pointed out to me a widget available at MacWireless.com that scanned for most used channels and showed me how to set a specific channel for the Airport Extreme.  The problem was that the signal was intermittent and the computers couldn't always connect.  I live in New York City, and from my apartment can pick up anywhere from 2-10 other wireless routers at any given time, and so the tech suspected interference, and I he was almost certainly right.  I changed to a specific channel and have been running just fine ever since.

I also lowered the encrytion level to WEP, figuring that maybe the more extreme encryption modes might be a part of the problem.

Well imagine my surprise when today I went to check the weather and saw on the wireless widget that not only was my network running on the assigned channel but four others were as well, two of them having names with regular English words, and the other two having names with hex digits, like AC1367BFF16.  I've seen these before, as far back as when I was using a NetGear router to manage this network, but never gave them a second thought until my suspicions were raised by us all suddenly sharing the same channel (and we weren't when I set this up).  

I went into my router control panel, changed the channel, and all of these other networks disappeared.  I set the Airport to "closed network" hoping that if they can't see me they can't hack me, but I really need for all of this to be secure, and I really need to not be sponsoring people bootlegging Brittany Spears music, so I'd like to lock this down as best I can and still have it work.

I'd also like to know, comprehensively, whether these three computers are the only ones on the system, or not.  

Any suggestions / advice?

Answer : Problem: Is my Airport Extreme being hacked?

Suggestion: Steve Gibson and Leo Laporte have created an excellent series of podcasts addressing the subject of wireless security.  See "Security Now!" at http://TWIT.tv or on your favorite podcast aggregator.

WEP security has been shown to be weak and breakable. (WPA is much stronger, but not as widely supported in older machines.) However, some of the other wireless hubs in your area are probably open, requiring no password to use.  With such an easy connection available, internet moochers and dot-cons are not likely to take the time to break your password.

The appearance/disappearance of other networks is not likely to be related to changing your hub.  

Since your wireless is invisible to scanners, and has a password, the only thing left is to turn on MAC address filtering (these are called M.A.C. addresses for technical reasons, but this refers to the hardware address of a device, not to a "Macintosh" per se.)  This feature prevents unwanted connections by limiting them to the addresses in the hub's list.  That is, only the hardware addresses in the list will be allowed to communicate with the hub.

Note that it is humanly possible to defeat just about all of this, but it would be such a large outlay of time and resources that any hacker-wannabee-teenager would go after the eaiser targets first.