finger-warmup_(beginner)

finger-warmup (beginner):web:160pts

A finger warmup to prepare for the rest of the CTF, good luck!
You may find this or this to be helpful.
finger-warmup.chals.damctf.xyz

Solution

サイトにアクセスすると以下のようなページだった。
site
site.png

<a href="un5vmavt8u5t5op1u94h">click here, if you are patient enough I will give you the flag</a>

クリックするとソースは以下に変化した。

<a href="bz3nokz7rkmxtef7v5u0v">click here, if you are patient enough I will give you the flag</a>

毎回クリックするとhrefが変わるようだ。
手動でたどるのは難しそうなので以下のhrefhref.pyで行う。

import re
import requests

href = ""
response = ""

try:
    while True:
        url = "https://finger-warmup.chals.damctf.xyz/" + href
        response = requests.get(url)
        nexthref = re.search("<a href=\"(?P<next>.*)\">", response.text)
        href = nexthref.group("next")
        print(href)
        print(response.text)
except:
    print(response.text)

実行する。

$ python -u hrefhref.py | tee log.txt
un5vmavt8u5t5op1u94h
<a href="un5vmavt8u5t5op1u94h">click here, if you are patient enough I will give you the flag</a>
bz3nokz7rkmxtef7v5u0v
<a href="bz3nokz7rkmxtef7v5u0v">click here, if you are patient enough I will give you the flag</a>
c79rvw7rf823hwad0fle2
<a href="c79rvw7rf823hwad0fle2">click here, if you are patient enough I will give you the flag</a>
2bm1visowi7n5aoll322hs
~~~
<a href="de19g6949wfr4afo7xrqj">click here, if you are patient enough I will give you the flag</a>
24bago4w2bojwtrnotvdik
<a href="24bago4w2bojwtrnotvdik">click here, if you are patient enough I will give you the flag</a>
310491iil95gv69b6qpjp
<a href="310491iil95gv69b6qpjp">click here, if you are patient enough I will give you the flag</a>
Nice clicking, I'm very impressed! Now to go onwards and upwards! <br/><pre>dam{I_hope_you_did_this_manually}</pre>
$ wc -l log.txt
1999 log.txt

flagが得られた。
flag
flag.png
1000回ほどクリックすれば手動でも可能だった。

dam{I_hope_you_did_this_manually}