RC3 CTF 2017 - This is where I'd put my Home Page.. IF I HAD ONE [100]

This is where I'd put my Home Page.. IF I HAD ONE - 100 Points

http://13.59.6.98:80

First of all, maybe you need some reference before to solve this problem:

cURL

Points: 100
Tags: web 


This page won't seem to load.. what is happening???????? - Joker
13.59.6.98:80

Note: Flag is not in RC3-2017{}format

Use cURL for the first step

<meta http-equiv="refresh" content="0; url=C.html" /> <p hidden>R</p>

It is a piece of HTML's code, but the interesting part is:

url=C.html" /> /*and*/ <p hidden>R</p>

Now, try modification the url "http://13.59.6.98/C.html"

<meta http-equiv="refresh" content="0; url=3.html" /> <p hidden>C</p>

From here we know that is something weird, so let's dig it more deep

import requests
import re

url = "http://13.59.6.98"

while 1:
    r = requests.get(url)
    content = r.content.decode('utf-8')
    print (content, end='')
    url = "http://13.59.6.98/{}".format(re.findall("url=(.*)\"",content)[0])

And the result is:

<meta http-equiv="refresh" content="0; url=C.html" />       <p hidden>R</p>
<meta http-equiv="refresh" content="0; url=3.html" />       <p hidden>C</p>
<meta http-equiv="refresh" content="0; url=W.html" />       <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=33.html" />      <p hidden>W</p>
<meta http-equiv="refresh" content="0; url=M.html" />       <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=U.html" />       <p hidden>M</p>
<meta http-equiv="refresh" content="0; url=S.html" />       <p hidden>U</p>
<meta http-equiv="refresh" content="0; url=7.html" />       <p hidden>S</p>
<meta http-equiv="refresh" content="0; url=G.html" />       <p hidden>7</p>
<meta http-equiv="refresh" content="0; url=0.html" />       <p hidden>G</p>
<meta http-equiv="refresh" content="0; url=D.html" />       <p hidden>0</p>
<meta http-equiv="refresh" content="0; url=333.html" />     <p hidden>D</p>
<meta http-equiv="refresh" content="0; url=3333.html" />    <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=P.html" />       <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=33333.html" />   <p hidden>P</p>
<meta http-equiv="refresh" content="0; url=RR.html" />      <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=RRR.html" />     <p hidden>R</p>
<meta http-equiv="refresh" content="0; url=333333.html" />  <p hidden>R</p>
<meta http-equiv="refresh" content="0; url=DD.html" />      <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=1.html" />       <p hidden>D</p>
<meta http-equiv="refresh" content="0; url=RRRR.html" />    <p hidden>1</p>
<meta http-equiv="refresh" content="0; url=3333333.html" /> <p hidden>R</p>
<meta http-equiv="refresh" content="0; url=CC.html" />      <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=77.html" />      <p hidden>C</p>
<meta http-equiv="refresh" content="0; url=777.html" />     <p hidden>7</p>
<meta http-equiv="refresh" content="0; url=7777.html" />    <p hidden>7</p>
<meta http-equiv="refresh" content="0; url=R.html" />       <p hidden>7</p>
---------------------------------------------------------------------------
<meta http-equiv="refresh" content="0; url=C.html" />       <p hidden>R</p>
<meta http-equiv="refresh" content="0; url=3.html" />       <p hidden>C</p>
<meta http-equiv="refresh" content="0; url=W.html" />       <p hidden>3</p>
<meta http-equiv="refresh" content="0; url=33.html" />      <p hidden>W</p>

If you can see it create a combination : RC3W3MUS7G0D33P3RR3D1R3C777

After the "..R3C777" it will start again at the first website the "http://13.59.6.98/R.html" not actually the first website but the source code same as "http://13.59.6.98:80", so it's just doing a loop

flag:{RC3W3MUS7G0D33P3RR3D1R3C777}