cyber.gouv.qc.ca CTF1 Writeup

The Quebec Gouvernment launched a CTF platform with only a link as information.The link is https://www.cyber.gouv.qc.ca/ctf/ctf1.enc

We have to download an encoded file to begin…

Looking at the file, we see it is uuencoded ASCII text.

Now, we have a zip file. I’ll rename it first and then extract the content.

And it asked for a password. Let’s crack it!

Now… the whole content is ASCII and gibberish text.

I tried a lot decoding tools, algorithms and even created a script to count the number of repetitive sequences in a large string. Finally I had an idea. Looking at the last password we found, I figured it was a clue for the next and final step.

I loaded the file in cyberchef and used Citrix CTX1 to decode it.

And here it is.



                                  o$""$o
                                  $$  $$
                                   $$$$
                                   o "$o
                                  o"  "$
             oo"$$$"  oo$"$ooo   o$    "$    ooo"$oo  $$$"o
o o o o    oo"  o"      "o    $$o$"     o o$""  o$      "$  "oo   o o o o
"$o   ""$$$"   $$         $      "   o   ""    o"         $   "o$$"    o$$
  ""o       o  $          $"       $$$$$       o          $  ooo     o""
     "o   $$$$o $o       o$        $$$$$"       $o        " $$$$   o"
      ""o $$$$o  oo o  o$"         $$$$$"        "o o o o"  "$$$  $
        "" "$"     """""            ""$"            """      """ "
         "oooooooooooooooooooooooooooooooooooooooooooooooooooooo$
          "$$$$"$$$$" $$$$$$$"$$$$$$ " "$$$$$"$$$$$$"  $$$""$$$$
           $$$oo$$$$   $$$$$$o$$$$$$o" $$$$$$$$$$$$$$ o$$$$o$$$"
           $"""""""""""""""""""""""""""""""""""""""""""""""""""$
           $"                                                 "$
           $"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$"$
				Classement
	   *****************************************************
	   * Contributeur			Score	       *	
	   *****************************************************
	   * nic-lovin				  6	       *
           *****************************************************
  	   * pll25 				  6	       *
	   *****************************************************
           * Felix B				  3	       *
	   *****************************************************	   
	   * Victor Duplenschi		          2	       *
	   *****************************************************	   
	   * 0xc0ffee				  2	       *
	   *****************************************************
	   * Etjenne 				  2	       *
	   *****************************************************
	   * h3xit 				  1	       *
	   *****************************************************
	   * Guillaume Labbé-Morissette		  1	       *
	   *****************************************************
           * Sideni 				  1	       *
	   *****************************************************
	   * PathetiQ				  1	       *
	   *****************************************************
           * Nate				  1	       *
	   *****************************************************

	   Vous avez trouvez, consultez la page suivante pour nous le faire savoir.
	   https://www.cyber.gouv.qc.ca/ctf/*************************
	   	 
           Merci d'avoir participé! :D

Going at the link provided we are greated with this message.

Thank you to the Department of Cyber Security of Quebec.

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