Articles in the CTF category

  1. IceCTF 2016 - Thor is a hacker now

    Challenge description:

    Thor has been staring at this for hours and he can't make any sense out of it, can you help him figure out what it is?

    The text file provided is just a hexdump produced with xxd. xxd actually has a feature to reverse a hexdump back into the original file, from there I identified the resulting file's format with the file command. It was an lzip. Extracting the lzip resulted in the following image:




    Commands that were run in order:

     xxd -r thor.txt > thor.bin
    → file thor.bin
    thor.bin: lzip compressed data, version: 1
    lzip -d thor.bin
    → file thor.bin.out
    thor.bin.out: JPEG image data, JFIF standard 1.01
    → mv thor.bin.out thor.jpg
  2. IceCTF 2016 - Vape Nation

    Challenge description:

    Go Green!

    They provide a png called vape_nation.png:

    vape nation

    With the hint I figured it must be a green filter of some sort so I loaded up Stegsolve and checked out the green plane filters. Green plane 0 resulted in the following:

    solved nation

    Looks like a flag :)