Time-Shift: Veritas liberabit vos
The truth shall set you free

One, Two, Trimix

August 5th, 2021

It’s been about 8 years now, since I started my journey as a diver. From PADI OWD over CMAS**/*** to Trainer-C and dive Instructor in 2019, all of my diving “career” has been pretty much standard. Last year then I took my first steps into the area of technical diving with the DTSA TEC Basic certification. A few weeks ago finally I stepped up the game a notch by attaining my first Trimix certification (DTSA Trimix* / CMAS Normoxic Trimix Diver).

Apart from the Apnoe, Sidemount, UW photography / videography and rebreather certifications, this pretty much brings me close to having all the certifications in VDST. A DTSA Trimix** (CMAS Hypoxic Trimix Diver) is certain to follow at some point in the future. But at the moment I want to invest more time into honing my diving skills and furthering my instructor levels (diving instructor level 2 and instructor for technical diving are both in the making šŸ˜‰ ).

Veni, vidi, vici

October 10th, 2019

About 2 and a half years ago, I started my long term goal of becoming a dive instructor in my dive club. Last saturday this plan was brought to a successfull end in Deep Blue Diving Fuerteventura.

In order to get there, me and my TL* aspirant buddies had to endure quite some hardships. Apart from exams under water, we also had to show that we are capable above water, both as an exam, but also since the weather conditions where anything but favorable. More than once we had to cling desperately to the boat, getting our equipment in, while the atlantic ocean was hitting us with high waves and howling wind.

In the evening, though beat and tired, there was stuff to learn and dives to prepare for the next day. You could often see us playacting out how a specific excercise should work out under water the next day. Every now and than it worked out quite differently. But due to our good teamwork and the stubborn will of everyone to see this thing through, in the end, we all managed to achive the wanted result.

Very tired but glad no to have faltered, we all landed in Stuttgart on Thuesday. I came to Fuerteventura to get my TL* license, but I came home with much more than that: A bunch of new friends :-).

Aaaannd…. Action!

September 19th, 2019

Last Sunday I had the unique opportunity and pleasure, to take part in a small feature, shot at Kreidesee Hemmoor, for the child program 1, 2 oder 3. The feature was produced by Mingamedia GmbH and the underwater recordings were done by Jens-Uwe Lamm from uw-Film.

Luckily I did not have to step in front of the camera (I’m a bit camera shy :-D) but was only there to help light the scene and provide assistance if necessary. So my main task was “Shut up and stay out of the camera”, which I’m apparently good at :-P. Julian, Marven and Helge from my dive club (Tauchsportgemeinschaft SCUBI e.V. Stade) had to do all the hard work.

Unfortunately the weather conditions and the visibility left a lot to be desired. So my lighting became more important than we originally though. Holding the light in the right direction, keeping an eye on the camera and the man behind it (so I could move where he needed me) and keeping an eye out for my buddy at the same time, is nothing if not challenging.

Spending some much needed light (Photo: Jens-Uwe Lamm from uw-film)

After the first scene at the wreck of the Hemmoor was shot, I could relax a little bit, while my buddies had to film an over water scene in a small boat that the dive center at the Kreidesee kindly lend us for the shoots. First on the pier and later on in the water. The perfect opportunity for me to get out my camera gear and take some pictures of the shooting.

Eventually both scenes where also successfully captured and we used the boat to get to the destination of our next and final shoot, the big white. Finding that shark from the surface, when you’ve never seen the landscape from this side of the water surface isn’t as easy as we’d though. But Jens showed us the right direction. Eventually the last scene was captured and Jens had the opportunity to shoot some B-Roll and make a group picture.

The group behind the feature (Photo: Jens-Uwe Lamm from uw-film)

All in all it was a very interesting and challenging opportuniy and I am greatfull to had the chance to be part of it.

New Gallery for UW Photography

October 30th, 2018

I finally got my gear together to take my Nikon D750 under water (Nauticam NA-D750). So I’ve added a new gallery to my website to show off the pictures I’m making while diving. At the moment all my pictures are made in Hemmoor (Kreidesee Hemmoor) where I do my diving on the weekends. But other diving spots will sure follow. Enjoy! And if you like them, do leave a comment and tell me what you think!

CuraƧao 2015 – A vacation to remember.

November 13th, 2016

Finally found the time to add the picture of my CuraƧao vacation from 2015 to the album. This truly was one awesome vacation. CuraƧao… I’ll be back!

 

The connection horror or how I hacked my own data

November 29th, 2015

A lot of people know the situation: You get a new and fast Internet connection. But your provider is a support nightmare. He hands you a practically black boxed router that automatically gets its connection data from the Internet and you have no chance of ever getting this data. After all.. why would you.. isn’t it much easier this way? Well.. let me tell you a little secret the providers don’t like to be advertised that much: Not only do they push the configuration to your new router, but they can also change it ANYTIME they want. If you have a regular setup like most people it looks like this:

Network

(Given, not everyone has a NAS at home. But they become more and more common as the devices become more simple and the data people want to store (like e.g. Audio and Video Data) needs to be shared between devices in the network. So for the sake of this article lets assume the regular user has some kind of network capable storage. Technically even a smartphone or a wifi enabled HiFi system is a network attached data storage but lets keep it simple). In this kind of setup that we see in the above picture, the Router that you use is the only barrier between your data (or device that holds your data) and the Internet. Suddenly a device you though just “provides you with internet access” becomes the only thing between your privacy and total disclosure of your private data to the world! Worse yet: even if you are as naive as to assume you provider will never do you harm, will never be hacked and never be forced by the government to give them access to your data, there is hardly a month were security groups in the Internet and from companies don’t find horrific bugs in common router firmware. With the providers being the only ones who can update your router, you have to put total trust in them to do so in a timely manner. Sadly they usually are way behind when it comes to updating the devices. So obviously this is a setup that is not acceptable. A possible solution would look like this:

g10Its possible but it has a few rather bad downsides:

  • You waste power for a device you practically don’t use (the provider router).
  • The provider (or someone who hacked it) can still do stuff to the other router and close ports or mess with connections.
  • You still need to use the provider router for the SIP connection because you don’t have the login data for that.
  • Your connection speed might drop from having two firewalls and 2 NAT systems behind each other.
  • In worst case scenarios you can’t open ANY Ports towards your network because your provider doesn’t want it.

Its obvious that the best solution would be to have your own router (for me this is my Gentoo server) and telephone system (Asterisk in my setup) running that you can maintain and implement your own security plan as needed. When I switched my Internet provider this week (for a lot more speed) I had exactly this problem. They just give you a router (FritzBox) and nothing else. For me it was clear from the beginning that I was going to use my own solution as I have been for the last 4 years. This is the story of how I managed to do just that.

My first idea (that I had before I even had the thing in my hands) was to hack the router right after it had downloaded the configuration from my provider. I knew from articles in the Internet that there was a slim chance of getting a telnet daemon running on the FritzBox and connecting to that. However when the device was done downloading the data, it became clear pretty fast that this door was slammed shut by my provider. In fact there was no getting into that router from any angle. It took me the better part of a day to realize that this idea was a dead end.

I needed a new plan… and I had one. I knew from experience, that most companies don’t take security that seriously. So I though to myself: “Why should that router send all the login data encrypted over my DS Line?”. After all who really has the capabilities to sniff a very high frequency modulated signal in a cable that is mostly under ground (yes the government has, but they can just get that data if they want to). Fortunately the FritzBox has a sniffing program integrated for all Interfaces designed for customer support problems (horrifying I know but in that moment.. pure gold!). It records all packets send over a specified interface in the wireshark format. No sooner said than done I had a neat amount of PPPOE packages on my hard drive recorded during the login procedure via DSL. It didn’t take me to long to find the data that I was looking for. 3 different PPPOE connections. One for the Internet line, one for the voice channel and a third one for the TR-096 channel (provider remote access for touter configuration)! It was unencrypted as I though and the passwords and usernames where plaintext *Place facepalm and happy dance here*.

The last thing that was missing, was the username and password for the sip connection to my provider. And here I hit another dead end again. While PPP login using unencrypted PAP authentication is not that unusual, the SIP protocol has per standard an encrypted HTTP Digest challenge as login procedure. Though I could easily get the username (it was unencrypted of course :-/) it proved impossible to get the password this way (Technically it wasn’t impossible, but I would have had to put an immense amount of CPU/GPU time and energy into reverse calculating that has to a password password. Considering it turned out to be 8 characters long, that might have taken month, if not more, of a permanently running cracking program). But I was not about to give up that easily. After all as Jean-Luc Piccard once said: “Things are always impossible until they’re not!”. I needed yet another plan.

I remembered that though I did not know that password, neither did my router when I first unpacked it. I started digging into the TR-096 protocol. And there I found the weak link I was looking for. Although TR-096 uses HTTP as means of transport it is recommended to use HTTPS for obvious security reasons. My provider of course did not. When I saw the CPE management URI starting with http:// I knew I was onto the solution. I set my router back to its original state and disconnected the DSL cable. After rebooting the box, I immediately started the sniffer on the Internet line.

At first I was only getting rather useless PPPOE session data (PADI;PADO;PADR,PADS) or chunks of TCP data that wasn’t readable. I already became somewhat frustrated when the sniffer hit gold.A series of HTTP packages! I quickly put them together (they where fragmented) and the result looked something like this:

POST /live/CPEManager/CPEs/Auth_Basic/avm/ HTTP/1.1
Host: ***.***.***.***:80
Content-Length: 2776
Content-Type: text/xml; charset=”utf-8″
SOAPAction: “cwmp:Inform”

<soap:Envelope xmlns:soap=”http://schemas.xmlsoap.org/soap/envelope/” xmlns:soap-enc=”http://schemas.xmlsoap.org/soap/encoding/” xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xmlns:xsd=”http://www.w3.org/2001/XMLSchema” xmlns:cwmp=”urn:dslforum-org:cwmp-1-0″>
<soap:Header>
<cwmp:ID soap:mustUnderstand=”1″>100</cwmp:ID></soap:Header>
<soap:Body>
<cwmp:Inform>
<DeviceId>
<Manufacturer>AVM</Manufacturer>
<OUI>00040E</OUI>
<ProductClass>FRITZ!Box</ProductClass>
<SerialNumber>************</SerialNumber></DeviceId>
<Event soap-enc:arrayType=”cwmp:EventStruct[4]”>
<EventStruct>
<EventCode>7 TRANSFER COMPLETE</EventCode>
<CommandKey></CommandKey></EventStruct>
<EventStruct>
<EventCode>M Download</EventCode>
<CommandKey>*************</CommandKey></EventStruct>
<EventStruct>
<EventCode>4 VALUE CHANGE</EventCode>
<CommandKey></CommandKey></EventStruct>
<EventStruct>
<EventCode>1 BOOT</EventCode>
<CommandKey></CommandKey></EventStruct></Event>
<MaxEnvelopes>1</MaxEnvelopes>
<CurrentTime>0001-01-01T00:02:00</CurrentTime>
<RetryCount>1</RetryCount>
<ParameterList soap-enc:arrayType=”cwmp:ParameterValueStruct[8]”>
<ParameterValueStruct>
<Name>InternetGatewayDevice.DeviceSummary</Name>
<Value xsi:type=”xsd:string”>InternetGatewayDevice:1.4[](Baseline:2, EthernetLAN:1, ADSLWAN:1,ADSL2WAN:1, Time:2, IPPing:1, WiFiLAN:2, DeviceAssociation:1), VoiceService:1.0[1](SIPEndpoint:1, Endpoint:1, TAEndpoint:1), StorageService:1.0[1](Baseline:1, FTPServer:1, NetServer:1, HTTPServer:1, UserAccess:1, VolumeConfig:1)</Value></ParameterValueStruct>
<ParameterValueStruct>
<Name>InternetGatewayDevice.DeviceInfo.HardwareVersion</Name>
<Value xsi:type=”xsd:string”>*********************</Value></ParameterValueStruct>
<ParameterValueStruct>
<Name>InternetGatewayDevice.DeviceInfo.SoftwareVersion</Name>
<Value xsi:type=”xsd:string”>************</Value></ParameterValueStruct>
<ParameterValueStruct>
<Name>InternetGatewayDevice.DeviceInfo.SpecVersion</Name>
<Value xsi:type=”xsd:string”>1.0</Value></ParameterValueStruct>
<ParameterValueStruct>
<Name>InternetGatewayDevice.DeviceInfo.ProvisioningCode</Name>
<Value xsi:type=”xsd:string”>*****</Value></ParameterValueStruct>
<ParameterValueStruct>

….

Of course there was real data in there. I just put the stars in to cover up sensitive information. Somewhere in this chunk of data (apart from all the config data that I already had from my other sniffing attempts) if found two junks that where like the second coming for me on this day:

<Name>InternetGatewayDevice.Services.VoiceService.1.VoiceProfile.1.Line.1.SIP.AuthUserName</Name>
<Value xsi:type=”xsd:string”>*************</Value>

<Name>InternetGatewayDevice.Services.VoiceService.1.VoiceProfile.1.Line.1.SIP.AuthPassword</Name>
<Value xsi:type=”xsd:string”>*************</Value>

Bingo! The last puzzle pieces to my odyssey! As a last measure of verification, I flashed my router with a de-branded firmware and entered the data that I had collected in the appropriate interfaces (to make sure that there was no other special stuff in that old firmware that was needed to make the connections). And it worked like a charm. Even though it might not seem like such a big deal for some.. for me those two days of hacking to get my own data (after all I pay for that connection) was quite an experience in itself. Especially since I was successful! Another win for free choice and against oppression :-P.

And the moral of the story? Thank god most ISP’s are to lazy to implement real security. If all those connections would’ve been encrypted, it would’ve been nearly impossible to get all that data. Crazy and scary at the same time :-P.

Fixing bugs the right way: Be a scientist

April 9th, 2015

So lately a though started to form in my mind that has been there for quite some time but due to environment has become more and more dominant in my head. A lot of times when I see people dealing with bugs, their first reaction is “This can’t be a problem with my code!”. Though understandable to some point, this is of course bad for the project (and for the team moral). Before long you have bugs floating from one to another, being closed, reopened again and start that nasty circle all over. Most of you will probably know what kind of bugs I’m talking about. So what to do about this? The answer is simple: Be what most of you have been trained to be! Be a scientist! I’ve come about this very intriguing graphic a few days ago:

 

A-Rough-Guide-to-Types-of-Scientific-Evidence

Though technically oriented towards medical students this pictures pretty clearly what evidence you can trust easily and what might be a bit fishy. The first thing that catches the eye is that expert opinions are lowest in the list of trustworthy evidence. In other words: The phrase “This can’t be a problem with my code!” said by no matter how much of an expert is basically worthless when it comes to fixing bugs using the scientific approach. Event a hint where the problem may lay is to be regarded as such.. a hint and no more. Especially if you tell yourself that you can not be the origin of that bug always remind yourself that you can’t be sure unless proven right.

The next step on the list is an experimental approach. This is what you’ll see most in code debugging and bug hunting. Changing values or code and see how it reacts to that changes and then extrapolate from that reaction. Though most people would guess this to be a good approach it really is not. Because this way all you get is more data and most of the times more puzzles instead of solutions.There are a million things that can go wrong using this approach. The code might be time critical and only fail if run without stopping by the debugger. Values might be different using a debugging approach. And last but not least: you might simply run your debugging code on different hardware then the real thing.

The next three steps are basically only good for data collection and finding clues as to where the bug may lay. Sometimes this gives you a really good insight and helps you track the problem faster. But normally this would be the job of the QA department. They are responsible to find a way to reproduce the bug and include that report in their bug report. In 90% of the cases we will be writing deterministic software. Meaning: even if we use some kind of weak random generation using predefined seed, the software will always behave the same way when run on the same hardware and giving the same input. If it doesn’t (and believe me thats really hard to prove) then your hardware is broken. So as long as you have not proven your hardware broken and you are sure your program is deterministic, there is always a way to find reproduction steps. And once you have those you’re on a good path.

Which leaves the last two possibilities. The first one being randomized tests (which is might or might not be possible depending on your software and the way you input data) and the last one being a scientific approached review of the code.

Randomized tests are a good subject to be done automatically by your build servers. They can find bugs and you’ll always have the input data that generated those bugs (which makes finding reproduction steps pretty easy). Depending on your program this might be pretty hard to achieve, however you should at least plan in some automated testing before you even begin to write code. In an optimum case you even have the whole continuous deployment pipeline ready to use before you even start to write a single class.

After you’ve done all this and moved through all the fact finding steps you should have a pretty fair idea where your bug is hiding. If not. Start from the beginning. After all: science means that you are looking for the truth and not “your idea of the truth”. So don’t start bug hunting trying to prove it is not your code that is broken. Start bug hunting trying to prove what code is broken. If it turns out it wasn’t your stuff, all the better. Comment the bug and send it along to the code owner. And if it turned out that you did some really bad stuff: Thank god you found it. Every truth is god. And if you learn from your (or from others) mistake it will not happen again.

So once you have all the information and know where to look, start reviewing your code. I like to do this by stepping through it with a debugger and look at what I’ve really got. More often then not the data I see is not what I expected and I can find the problem really quickly. Sometimes its hard to track where that data is coming from. But at least now you know whats causing the symptoms. If you have proven that its not your code that causes the problem, but the data that comes in from somewhere else, its ok to collect all the infos in the bug report and pass it on to the person you think knows that code the best. After all he might be able to given an expert opinion :-P.

The “No Facebook” Group – A story about modern discrimination

November 5th, 2014

There is this “Thing” thats been bugging me fore quite some time now and thats been getting worse and worse the last few years. Its what I like to call the “facebookisation” of the Internet. Maybe its even Facebook itself that I perceive to be a foreign body in the Internet organism.

It all began quite some while ago with me (a normally very early adopter when it comes to new things on the Internet) not wanting to have a Facebook profile. It wasn’t only about the idea of giving someone, who clearly has no right to it, a one time profile of my personal information. It was about the fact that I was practically inviting this “facebook person” to my every day life. Yes I know a lot of you have the naive idea of filtering information that flows to Facebook. But face it its nonsense… in fact I really told (and tell) everybody that. They laughed at me (and still do). When all that NSA stuff came out (and still comes out), I though people would finally agree that personal information flow has to be limited in some way.. that no one company (worse yet a company under the influence of a completely broken down law system) should get that much information. But people simply don’t care. And I have to admit that I don’t care about them not caring. It’s their life. If they get shot at by a drone or vanish into thin air because they liked the wrong thing, it was their life to give.

But lately Facebook has reached about the maximum amount of “willing” users they can get (Q3 2014 its about 1.35 billion active user [1], not counting inactive accounts). So now (almost like in a dictatorship thats gotten as much advocacy they can get through normal methods) they slowly start making life harder for all the people not using Facebook (by increasing social pressure). This started with competitions where you could only enter if you are using Facebook and like stuff (can’t say I really care), went on to a lot of games where you actually get benefits from attaching you Facebook account to the game account (there I care more.. I’m a game dev.. I don’t like that) and lately whole services stop writing their own authentication processes and rely solely on Facebook for that!

Not only do those companies provide Facebook (and thus the US government too) with free profiling data, but they’re also discriminating all non Facebook users by simply denying them their services! Thus again increasing the social pressure of joining Facebook (you can’t believe peoples reactions when I tell them I don’t use Facebook). This brings up a lot of very bad memories from history lessons and books I read about the past history of Germany! And it shows how fast our society is willing to forget their past when it supports their laziness. I would say “beware of the beginnings!” but I’m afraid we’re already past the point where people would be willing to abstain from Facebbok. Just because governments use private companies today to do their dirty work for them does not mean they are not involved!

So if you’re a dev (or better yet a game dev) and are writing an app or a web app or whatever, think about your authentication process before blindly relying on external services. There are open source variants for authentication procedures and you have a database for your stuff anyway! Stop discriminating people and start using your brain!

 

Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.

Benjamin Franklin

Snorkeling in Ibiza.

October 19th, 2014

Finally found the time to put up some pictures of our Ibiza vacation (me and my sister). I had my GoPro Hero3 with me and made a lot of picture during our snorkel tours. Apart from one day I was every day in the water at least once (2 days where diving and those pictures will follow soon). If you like snorkeling and seeing lots of fish and octopus then Ibiza is the right place to go. Don’t expect Caribbean fish life though. Its still the Mediterranean sea! My pictures can be found here.

One small step…

February 23rd, 2014

Its been silent here lately. For some part it was due to the fact that there was not much to tell (being without work really is utterly boring :-P). For another part it was due to the fact that I was pretty busy (looking for a job is boring too but a lot of work) and last but not least because the year 2013 has seen a lot of losses and disappointments for me and my spirit was to crushed to write something that would’ve been worth reading at all. Now this is the year 2014 and so far its been a lot better then the last one (I keep my fingers crossed that it stays that way). Some of the disappointments of the last year still echo into this one, but overall things are brightening up for me. For one thing I now not only found a new job, but I found a job in the games industry again! That not being good enough, I now work using C++ (which is kind of my “soul language”) and am developing a real 3D game thats not run in some alibi browser plug-in but directly on a mobile device! I’ve only been working at Fishlabs for about a month now but I already get thatĀ tingling in my fingers every time I enter the building which is a very good sign :-P. The team is great, the work so far is inspiring and the prospects are rather encouraging (Btw. if you’re a programmer and are looking for a job in the games industry, head over to Fishlabs.net and see if we have a post that would fit your profile! We’re hiring!). So on the job side of life its been a very gentle year so far. In the other areas of my life it has at least been a calm year (which is kind of an improvement regarding all the catastrophes I had in the last one). Now spring is coming in Germany and we all know that spring usually brings out the good stuff of the year :-P. So to quote my favourite Singer: “The best is yet to come…”.