Public Wifi – Coffee Shop Security

I went to a coffee shop today to do some work. Update a few documents and get some random things I have been putting off.    As always I log onto the coffee shop wireless and connect to my VPN.  (read other articles here and here).

After completing the items I had set out to do.  I took some time to do some poking around on the wifi.  Since wireless is basically you sharing a network with others, it is easy to see what people are doing.  I used a simple nmap query to see who my neighbors are.

That scan showed me 5 active people and their IP.   It also let me know that the router had HTTP running.   Since I already knew the PC names and what ports they had open. (some one had a web server running).  I decided to look at the wireless router.  To my surprise it was running DD-WRT, my favorite router firmware.    DDwrt is a very powerful router firmware that can turn a basic wireless router into a great device.

However there are a few settings you need to understand when using DDWRT.  One in particular is to disable the default status page for unauthenticated users.  This page shows a lot of information that you don’t want snooping people like me to see.   Things like:

  • Public IP
  • Firmware version
  • Device Type and name
  • Connected users (IP address, mac address, dhcp lease)

Not only was this on but I was able to also see the other computers on the network (with out doing a nmap scan).   So everyone who had connected in the last 2 hours pc was listed on this page.  I decided to push up a pic.  My pc is called TP2.


This is scary to me because someone took the time to use a great opensource Firmware but not the time to properly secure it.    It is also interesting to see the number of android devices that were using the wifi.  I guess the same is true for iPhone devices.

I can’t stress this enough, when on public wifi use a VPN.  If you don’t have one.  Head on over to and subscribe or purchase.

The other item on the list is BT, that is the backtrack vm that I started to do some network sniffing.

1 thought on “Public Wifi – Coffee Shop Security”

  1. Not to change the thread, but due to the wholesale cost of raw coffee beans. One would expect the sales of coffee makers and espresso machines to be a popular item for Christmas this year! Just Sayin!

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