Eavesdrop is a neat little network monitoring/packet capture utility written by Eric Shore Baur. As far as these sorts of apps go it is fairly basic being limited to only capturing TCP packets, but where it scores is in extreme ease of use.
If you are interested to see what is going on in the background on your network then this application can make for a fun little diversion and may possibly enlighten you in the process. When you launch the app the first thing you will see is a blank window with a number of buttons along the top. Clicking on the Start Capture button will in most cases prompt you for an admin username and password ( unless of course you are already logged in as an admin in which case it will prompt for your password ). After that you will probably not see anything happen immediately. If you now go to your browser and open a web page you will see a burst of activity and the window will begin to display information about the conversation going on between your PC and the Internet. Each row of data displayed shows a communication between a source and a destination.
If you double click one of these rows another window will appear showing you detailed information about that conversation. Clicking on Payload and Raw Data will show the actual data that was transmitted, whilst the Images tab will display the actual images transmitted as part of a web page ( for parts of a conversation that involved the transmission of images ).
Where this type of utility is interesting is in demonstrating just how open many network applications are and how easily important information such as usernames and passwords can be obtained. As an example of this start a network capture session then fire up Mail. In the captured data you should see a row with your PC’s IP address as the source and a Port of 110. Double click this row and you will see the Raw Data of that conversation displayed something like the image below :-
As you can clearly see your email username and password are there for the whole world to see. Now imagine that this conversation had been recorded by someone monitoring conversations on a wireless network in a coffee bar and you can see that the skills necessary to obtain this sort of data are within reach of anyone.
Makes you think doesn’t it ?
[tags]mac, osx, network, sniffer, eavesdrop, security[/tags]
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