[ 1day_1chall ] :: [ Day 2 – Watson ]

[ 1day_1chall ] :: [ Day 2 - Watson ]

<blockquote><strong>Descrição: </strong><em>Qpcihz... pacyjpehi h pavhjoceh fh glos fh KWO gly iy yzmhzcjp ye xccd://qqq.kwo.vhb/zyqi/ichjoyi/2008/fymyewyj/mhfy_122908, y ipol yiip kjpiy fhofp, gly y' p kapv. Dtcxhz whewp!</em></blockquote> Trata-se de uma mensagem criptografada. Aparentemente existe um endereço de uma página web: <em>xccd://qqq.kwo.vhb/zyqi/ichjoyi/2008/fymyewyj/mhfy_122908</em>. Então começamos a analisar utilizando algumas "colas": <ul> <li>X=h</li> <li>C=t</li> <li>D=p</li> <li>Q=w</li> </ul> Ciphertext: ABCDEFGHIJKLMNOPQRSTUVWXYZ Plaintext:   ??<strong><u>tp</u></strong>???????????????<strong><u>w</u></strong>????????<strong><u>h</u></strong>?? Realizando as substituições acima, temos: <blockquote> <p style="text-align: left">wPtIHZ... PAtYJPEHI H PAVHJOtEH FH GLOS FH KWO GLY IY YZMHZtJP YE http://www.KWO.VHB/ZYwI/ItHJOYI/2008/FYMYEWYJ/MHFY_122908, Y IPOL YIIP KJPIY FHOFP, GLY Y' P KAPV. pTthHZ WHEWP!</p> </blockquote> Ainda não é o suficiente para quebrarmos esta frase secreta. Para ter uma idéia mais concreta do que pode ser, utilizamos o site <a href="http://www.quipqiup.com/index.php">http://www.quipqiup.com/index.php</a> que é excelente para resolver criptogramas e para nossa surpresa conseguimos descobrir a primeira palavra: <strong>Watson</strong>!<img class="alignnone size-full wp-image-1895" src="https://ctf-br.org/wp-content/uploads/2016/02/day02_watson.png" alt="Day2_Watson" width="1139" height="115" /> Então sabemos que <strong><em>Qpcihz </em></strong>é o nome do nosso caro “<em><strong>Watson</strong></em>”. Reparamos que o endereço da página também ficou mais compreensível, descobrimos as palavras “<em><strong>n</strong><strong>ews</strong></em>” e “<em><strong>stories</strong></em>”! Isto nos permite adicionar mais pistas, então vamos substituir com tudo que encontramos até o momento: <blockquote><strong><u>Watson</u></strong>... <strong><u>a</u></strong>A<strong><u>tera</u></strong>E<strong><u>os</u></strong> <strong><u>o</u></strong> <strong><u>a</u></strong>AV<strong><u>orit</u></strong>E<strong><u>o</u></strong> F<strong><u>o</u></strong> GL<strong><u>i</u></strong>S F<strong><u>o</u></strong> KW<strong><u>i</u></strong> GL<strong><u>e</u></strong> <strong><u>se</u></strong> <strong><u>en</u></strong>M<strong><u>ontra</u></strong> <strong><u>e</u></strong>E <strong><u>http</u></strong>://<strong><u>www</u></strong>.KW<strong><u>i</u></strong>.V<strong><u>o</u></strong>B/<strong><u>news</u></strong>/<strong><u>stories</u></strong>/2008/F<strong><u>e</u></strong>M<strong><u>e</u></strong>EW<strong><u>e</u></strong>r/M<strong><u>o</u></strong>F<strong><u>e</u></strong>_122908, <strong><u>e</u></strong> <strong><u>sai</u></strong>L <strong><u>essa</u></strong> Kr<strong><u>ase</u></strong> F<strong><u>oi</u></strong>F<strong><u>a</u></strong>, GL<strong><u>e</u></strong> <strong><u>e</u></strong>' <strong><u>a</u></strong> KA<strong><u>a</u></strong>V. <strong><u>p</u></strong>T<strong><u>thon</u></strong> W<strong><u>o</u></strong>EW<strong><u>a</u></strong>!</blockquote> &nbsp; A frase ficou muito mais clara. Com um pouco de dedução conseguimos matar outras palavras, por exemplo: <ul> <li>“enMontra” &gt;&gt; “encontra”</li> <li>“saiL”           &gt;&gt; “saiu”</li> <li>“Krase”        &gt;&gt; “frase”</li> <li>“FoiFa”         &gt;&gt; “doida”</li> <li>“pTthon”      &gt;&gt; “python”</li> </ul> <blockquote><strong><u>Watson</u></strong>... <strong><u>a</u></strong>A<strong><u>tera</u></strong>E<strong><u>os</u></strong> <strong><u>o</u></strong> <strong><u>a</u></strong>AV<strong><u>orit</u></strong>E<strong><u>o</u></strong> <strong><u>do</u></strong> GL<strong><u>i</u></strong>S <strong><u>do</u></strong> KW<strong><u>i</u></strong> GL<strong><u>e</u></strong> <strong><u>se</u></strong> <strong><u>encontra</u></strong> <strong><u>e</u></strong>E <strong><u>http</u></strong>://<strong><u>www</u></strong>.KW<strong><u>i</u></strong>.V<strong><u>o</u></strong>B/<strong><u>news</u></strong>/<strong><u>stories</u></strong>/2008/F<strong><u>e</u></strong>M<strong><u>e</u></strong>EW<strong><u>e</u></strong>r/M<strong><u>o</u></strong>F<strong><u>e</u></strong>_122908, <strong><u>e</u></strong> <strong><u>saiu</u></strong> <strong><u>essa</u></strong> <strong><u>frase</u></strong> <strong><u>doida</u></strong>, GL<strong><u>e</u></strong> <strong><u>e</u></strong>' <strong><u>a</u></strong> KA<strong><u>a</u></strong>V. <strong><u>python</u></strong> W<strong><u>o</u></strong>EW<strong><u>a</u></strong>!</blockquote> Finalizamos o processo e descobrimos que a <u>flag</u> era a frase completa! <h2>FLAG</h2> <em>Watson... alteramos o algoritmo do quiz do FBI que se encontra em http://www.fbi.gov/news/stories/2008/december/code_122908, e saiu essa frase doida, que e' a flag. Python bomba!</em> <h3>CRIADO POR</h3> RTFM - Red Team Freakin' Maniacs