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HACKvent 2015: Day 9

09 Dec 2015

Challenge

The following sound file was also provided: Download MP3 Solution This was a very simple challenge. First we listen to the transmission and discover it spells out the nugget but some characters are turned into noise. We get:

The ?  character represents a character in the set [A-Za-z0-9] (because those are the only…read more.

 
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HACKvent 2015: Day 8

08 Dec 2015

Challenge

Link to website (may be down): http://hackvent.hacking-lab.com/xMasStore_wqbrGjHxxZ9YkbfiKiGC/index.php Solution I inspect the source of the website and take a look at the background image but that seems to be fine. There is nothing else of interest on the website so I figure this may require a brute-force attack. I then however find a cookie that is…read more.

 
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HACKvent 2015: Day 6

08 Dec 2015

Challenge We are given the following string:

Solution We can deduce by the amount of padding that this is Base32 encoded string. We use an online decoder and get:

Then we try various other things to decode the above string. I will admit I failed to find a proper solution until I received…read more.

 
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HACKvent 2015: Day 5

08 Dec 2015

Challenge You are given the following file: Download PDF File Solution So we open the PDF file to find 1 QR image in a ball. We scan it and we get the text Oooops ! . We then use an online tool to extract all images from the PDF (link). I do this because PDF files store…read more.

 
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Advent Of Code 2015: Day 7

08 Dec 2015

Challenge

Solution Wow this one was fun! I decided to use Z3Py, a theorem prover module for python. My solution essentially parses each command using regexp and adds the various boolean rules to a solver object. Finally, the theorem solver checks all possible values and prints out the results of every ‘wire’. Determining the answer is…read more.

 
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HACKvent 2015: Day 7

07 Dec 2015

Challenge

Solution This challenge was very easy to solve as I had completed the teaser earlier. First I convert the hexadecimal number provided (as it starts with 0x) to binary. The result is 625 bits (which does not divide nicely by 8 so it is probably not an ASCII message). However, its likely to be a…read more.

 
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HACKvent 2015: Day 4

07 Dec 2015

Challenge

Solution At first I was convinced this was a Vigenere cipher but this is not the case. After a clue from M from the hacking-lab IRC channel I was able to figure out the cipher used is the Scytale cipher. This is somewhat obvious as the -  characters from the nugget are all grouped at the end…read more.

 
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HACKvent 2015: Day 3

07 Dec 2015

Challenge This image was provided: Solution We clearly have to either scan every QR code or find the correct QR code. So we simply use an online tool that splits up GIF files based on their frames (link). We download all the frames (29 images exist so its likely that each frame corresponds to one…read more.

 
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HACKvent 2015: Day 2

07 Dec 2015

Challenge

Solution After some Googling I realise this is the Klingon language from Star Trek. I try some online translators (including Bing!) and it is clear that the message is a series of numbers that contain 0 or 1 only. This is most likely binary that represents ASCII text. I write a small script to convert each component…read more.

 
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Advent Of Code 2015: Day 6

06 Dec 2015

The Challenge

Solution I split up the solutions for part 1 and part 2. Was almost tempted to go for a numpy and scipy sparse matrix solution but a 1000×1000 matrix is small enough for a dense matrix. Part 1

Part 2

 
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