I Smell Packets


Solution to Where in The World is Chris?
July 23, 2009, 2:34 pm
Filed under: Berlin, Brandenburg Gate, Packet Challenge, Wireshark

I’m back from vacation. It was a blast! Where was I? Here is the solution to last week’s packet challenge.

Opening up the pcap file in Wireshark we see the following:

Picture8-1.jpg

A quick glance at the fourth packet reveals that this is a HTTP request to twitter.com. Note that in the Packet List Pane the fourth packet has been selected. In the Packet Details Pane the Hypertext Transfer Protocol field section has been expanded. In particular, this is a request to twitter.com for /cchristianson.

Another thing to take note of, is that there is also only one connection or flow in this particular capture. We know this because there is only one set of IP addresses, source port, and destination port combonation. In this case, it’s the one from 192.168.51.143:60538 <-> 168.143.162.116:80.

Back to the question at hand, ‘where in the world is Chris?’ Most of us are familiar with Twitter. One of Twitter’s features is the ability for a user to update their Location. This Location field is displayed on every user’s page. In this instance, this field reveals exactly where I am.

Looking through all these packets for my location would be a little tedious. To assist us in our efforts to find the right packet, Wireshark does have a nifty little search feature. To access the Search feature, go to the Edit Menu and select Find Packet. Search for the string ‘Location’ in the ‘Packet Details’ like so:

Picture8-2.jpg

This highlights the packet that contains my location. Selecting that packet and then expanding the Line-based text data: text/html section at the bottom, reveals all the content of the web page. Scrolling through that information will reveal the Location field as well as some numbers.

Picture8-3.jpg

The numbers are of course GPS coordinates. Inserting those coordinates into Google Maps or any other mapping software will reveal my exact location at the time, the Hilton Hotel in Berlin. Berlin is fantastic by the way.

Lot’s of people got this one right. Congratulations to Jorge Orchilles (@jorgeorchilles on twitter) for being the first. Thanks to everyone else for playing and following along.

I’ll be in Las Vegas next week attending Blackhat and Defcon. Send me a tweet or an email if you’d like to meet.

Before I go, here is one of the pictures I took while I was there. It’s of the Brandenburg Gate in Berlin.

DSC_5131a.jpg

References:

The TCP/IP Guide
Wireshark User’s Guide
Brandenburg Gate

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