PicoCTF-2019 Writeup
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  1. Forensics

WhitePages

PreviousWebNet1NextSo Meta

Last updated 4 years ago

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Problem

I stopped using YellowPages and moved onto WhitePages... but the page they gave me is all blank!

Solution

  1. If we inspect the file using a HEX editor, we can see that there are two types of whitespaces:

     $ xxd whitepages.txt | head
     00000000: e280 83e2 8083 e280 83e2 8083 20e2 8083  ............ ...
     00000010: 20e2 8083 e280 83e2 8083 e280 83e2 8083   ...............
     00000020: 20e2 8083 e280 8320 e280 83e2 8083 e280   ...... ........
     00000030: 83e2 8083 20e2 8083 e280 8320 e280 8320  .... ...... ... 
     00000040: 2020 e280 83e2 8083 e280 83e2 8083 e280    ..............
     00000050: 8320 20e2 8083 20e2 8083 e280 8320 e280  .  ... ...... ..
     00000060: 8320 20e2 8083 e280 83e2 8083 2020 e280  .  .........  ..
     00000070: 8320 20e2 8083 2020 2020 e280 8320 e280  .  ...    ... ..
     00000080: 83e2 8083 e280 83e2 8083 2020 e280 8320  ..........  ... 
     00000090: e280 8320 e280 8320 e280 83e2 8083 e280  ... ... ........
  2. We have the standard space (0x20), and the Unicode EM SPACE (0xE2 0x80 0x83). Since we have only two options, let's try to treat them as binary.

  3. Run the (which is commented) and get the flag.

Flag

picoCTF{not_all_spaces_are_created_equal_f71be4d2457dc2d068e8b1e7a51ed39a}

TXT File
script.py