Another day in WTH

31.07.2005 11:55

It began raining again over the night. Fortunately the ground is absorbing water fast enough this time and the tent is dry for now. I also dried all of my stuff yesterday on the sun, so I have very little motivation to get out of the sleeping bag or our tent.

I've attended a talk about exploiting PocketPC. Collin Mulliner showed us what an insecure platform Windows CE and all of its variants are. Because of certain features of this operating system (static addresses of the functions in libraries that are the same across all devices of the same type, even user processes can directly access hardware, etc.) writing exploits is quite easy. He showed a few examples ranging from displaying a message on the screen to making a call on a Windows CE based smartphone.

I've also been at the GNU radio workshop. After discussing basics of software defined radio, they showed us a basic FM radio receiver (they have basic building blocks like decimators, demodulators, etc. written in C for speed. These blocks are then connected with Python). Demodulation of the stereo signal used 25% of a 400 MHz processor if I remember correctly. A more interesting example was a transmitter that continuously transmitted words "All your frequencies are belong to us" on all CB channels. So no matter on which channel you tuned your receiver on your heard that voice.

Hacking on a traffic shaper configuration for the Meshnode people was also quite fun. I've set up a basic shaper, but the the configuration they would like to have is well beyond my knowledge.

Yesterday I also had my first experience handling a professional video camera. Since the video crew is running out of people I volunteered to record a talk by Indymedia people. I hope the recording is satisfactory.

Anyway, the official part of the camp is ending today. We plan to stay another night until Monday, perhaps helping to clean up the camp site. After that we're going to spend a few days in Amsterdam and then head back to Frankfurt to Wikimania.

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Some interesting photos

30.07.2005 20:31

Here are some assorted photographs of interesting things I found around the camp.

Beware of the man in the middle

It seems some people we ignoring warnings about different host keys when logging into their machines through the network. Yesterday, there was something like this written across the big display in What The Bar: "If you find your password here, change it quickly" followed by a list of passwords.

Unfortunately, a lot of POP3 and IMAP mail servers still don't support any kind of secure authentication (our beloved Siol included)

Bill Gates

Obviously, they buried Bill Gates here back in 8 August 1997 (that is the date of Hacking In Progress, one of the previous camps)

Fiber Grass

These people have planted some kind of a grass made out of fibreoptic cables. The sight is really impressive in the dark when each strand of grass emits blue light. Unfortunately, my camera can't take that kind of pictures.

Fun for kids

Some people have brought their kids with them. There are a lot of workshops organized for them (I wouldn't mind joining some of the workshops myself - water rockets are fun)

Wireless village

This the place I spend most of my time. Meshnode, ASCII, GNU Radio people are all gathered here, building bamboo antenna towers, broadcasting various stuff (for example: "All your frequencies are belong to us" simultaneously on all CB channels) and generally having a lot of fun. They are organizing a big party tonight that will include dancing for rain (like we don't have enough of it).

CCC rocket

This is the rocket of the Chaos Computer Club. They have set up a system of running landing lights that look like the beginning of a runway. I'm just waiting when one of those AWACS will try to land here.

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Interesting hardware

30.07.2005 16:49

Following two innovative transportation devices appeared near the What The Bar today. I'm not exactly sure if the exoskeleton is functional (it's built out of stuff commonly found in kitchens like utensils, part of washing machines, etc.) but the quadruped bike has certainly seen some use because someone broke of a pedal.

Kitchen exoskeleton

Quadruped bike

Some parts of the camp are connected to the net through equipment conveniently stored inside toilets. First time I saw that sign about dropping cables in the toilet, I thought someone was joking. Network admins said that toilets were the cheapest weather-proof cabinets for network equipment they could get.

Toilet net

Toilet net

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30.07.2005 6:28

Remember what I said what a nice place we found for our tent? Well, I take back everything I said. It was raining hard all night and I just woke up in water. Most of it is fortunately still below the bottom of the tent but speaking from experience it won't stay there for long. It looks like the whole field is under a few cm of water. My backback with laptop and other electronics is already soaking wet and my sleeping bag is also getting wet. My bed now has a squishy feeling and if I drop something on the floor in one corner of the tent I can see ripples in the water below going right to the other corner.

Perhaps taking that emergency shelter wouldn't be such a bad idea.

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They're on to us

29.07.2005 17:27

An AWACS-like airplane (big circular radar antenna on the back) just flew quite low over the camp. If the army is warflying I'm afraid they will be disappointed because the wireless network (at least IEEE 802.11b/g) continues to be in a very bad shape :) Unfortunately I was too late with my camera to take any pictures.

Anyway, today I'm mostly listening to talks (I've already attended a talk about honeyd, the honey net daemon and modsecurity, apache module for hardening web applications). I'm currently waiting for a talk by Eric Blossom about evolutionary computing. Maybe I'll learn something I can apply to Tablix.

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tcpdump tip

29.07.2005 14:13

If your tcpdump isn't showing any packets when you know it should be (like, you can ping another machine, but tcpdump doesn't show any packets on the wire), then the problem can be that it can't get a reverse DNS look up for the IPs in the packets it is receiving. You can use the -n option to turn off reverse lookups and solve this problem (or better, fix your DNS configuration).

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What The Bar

29.07.2005 10:50

What The Bar is offering following things today:

What The Bar

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LM77 & Lockpicking

28.07.2005 20:55

Opening talk

After listening to the opening talk at 11h I helped people in the wireless village set up a I2C temperature sensor in hardware for their Meshnode project. In the end it was just a matter of passing the correct parameters to the correct kernel module, but it me took several hours to come to that conclusion (if I only used google before jumping into Linux kernel source head first)

Raising of the bamboo tower in wireless village

Meshnode is software for setting up a wireless mesh network. This means that there is not central access points. Nodes in the network form ad-hoc wireless connections to nodes in their neighborhood and packets that cannot be sent from one node to the other (for example because the sender node does not see the receiver) are routed through nodes in the middle. Routing must therefore be dynamic. Special software is required to connect. They say that this kind of network is very scalable because the capacity of the network grows with the number of clients in it. On the other hand I think that meshing doesn't help with high concentrations of clients (like here on the WTH) since here the limiting factor is the congestion of the radio spectrum.

Main street

I also tried lockpicking for the first time at the workshop. I tried for more than one hour to open a simple lock with a lockpick and did not succeed. It's definitely much harder than it looks when you are just looking at professionals or in the movies. On the other hand, the technique presented last year on 21C called "striking" (it involves a special key and a small plastic hammer), is surprisingly simple. I've managed to open a standard lock on the second try.

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Interesting fact

28.07.2005 13:43

An interesting fact I heard today: there are 16 policemen in the camp (they are organizing a workshop on legal interception of data and can be recognized by a pink armband). WTH has /16 public network block, so that means there is exactly one policeman per /12 IP addresses.

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Wiring a tent

28.07.2005 8:50

Yesterday we wired our tent with ethernet from a neighbor's switch and power from somebody else's power strip. 10m UTP cable we brought with turned out to be a little too short, but we managed to exchange it for a longer one with someone who brought a cable that was too long.

Our switch

Since we had a small hub with us, some people that were further away connected to the net through us. This is basically how most of the networking is done here. Only big tents (for eating, talks, etc.) have been wired by the network crews. People nearest to the big tents are connected there. People further away then connect to their switches and so on. If I quote the organizers: places that bring more female than male connectors are the most popular. You can also get free cables at the entrance (guys there only want a beer if you don't know how to put a connector on the UTP)

The wired network is currently working with only slight glitches unlike the wireless network which is still unusable.

What is a tent without a penguin?

It has been raining most of the night and we had some light winds. So far, we only have moderate amounts of water inside our tent (my guess is because of the condensation). As long as the network connection is working we don't really feel the need to go outside :)

There will be an official opening talk later today. There is a stream available at (called SubEther Radio - it is also broadcasted on 105.1 MHz)

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Traveling to What The Hack

27.07.2005 22:55


Our train left Ljubljana at midnight. After enjoying six hours of mind boggling speed and comfort of Slovenian Railways we arrived at München a bit tired. There we sat on the first available bench and were immediately reminded by a friendly waitress that appeared out of nowhere, that it is not allowed to seat there unless we order something. We continued towards Amsterdam aboard an ICE train, enjoying a nerve wrecking game of ATC and a relaxing game of NetHack.


Amsterdam train station has surprisingly little information about local train timetables (we needed a ride on a local train from Amsterdam to Boxtel, nearest train station to What The Hack camp). There are many machines where you can buy tickets, but none of them is capable of displaying on which train you can use the ticket you just bought. An hour of trying to understand Dutch language and a conversation with a friendly conductor later we learned that we actually had to change two trains in order to arrive to Boxtel.


In Boxtel train station we saw a lot of people that looked similarly confused, carrying computer equipment and dressed in OpenBSD shirts. We decided to follow the crowd and we managed to get a free ride in a van together with a few fellow hackers.


When we arrived at the camp site and got our wristbands (they are used here as a proof of payment of the entry fee) it was raining. As the weather report predicted that the weather will only get worse, we went ahead and set up a tent in the first free place we found. Soon after we finished, the rain stopped and now it seems that we have managed to get a nice spot. Power and network connections are available nearby and neighbors are friendly :)

As I write this (20:56) we haven't yet gotten IPs for our computers (network admins are using an innovative DHCP peg system) and ieee802.11b wireless network isn't working as expected, so I can't publish this right now. We have just finished eating dinner and discussing our operating system preferences with the guy we shared the table with and we are now going to listen the pre-opening speech.

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Ready to go to What The Hack

26.07.2005 17:02

Finally, after all the troubles with airplane tickets (I can't belive you really can't get a cheap ticket if you don't own a credit card!) I have everything packed and ready to leave for What The Hack and Wikimania. Thanks to Loopus we are now traveling only by train. That way we will actually be in Boxtel sooner than by combining a flight to Frankfurt and a train to Boxtel.

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