Challenge Category: OSINT

Challenge: The author is running his own tech blog and is hiding a weird thing on its source. (Hey player, do you like copy-pasting things and throwing your waste in the bin?).
Author: cybersapien

Contents

Overview

  • I created this challenge as part of DC9111 2022 CTF.
  • This challenge was intended to be solved using OSINT and Python Beautiful Soup, that’s why its name is Lovely Soup.
  • Open Source INTelligence (OSINT) is the practice of collecting information from publicly available sources.
  • Beautiful Soup is a library that makes it easy to scrape information from web pages. It allows you to interact with HTML in a similar way to how you interact with a web page using developer tools. It can be used to fetch URLs from a website, which was intended for this challenge. Read more about Beautiful Soup here - https://www.crummy.com/software/BeautifulSoup/bs4/doc/.
  • This challenge was intended to be solved using Beautiful Soup but it can also be solved by just guessing Pastebin from challenge description (which many people did).

How to Solve

1). Simply, googling the text “cybersapien defcon” gives some websites links and also the description says “the author is running his own tech blog”. This gives us the hint to go for cybersapien.tech blog link.

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2). Next part of the description says “hiding a weird thing on its source” which is hinting for checking the source code of the blog. But there is lot of text.

3). Next part of description says “Hey player, do you like copy-pasting things and throwing your waste in the bin?”. This hints for some pastebin link.

4). Either we can directly search for pastebin in the source code or we can also use following Python Beautiful Soup code as the challenge name (Lovely Soup) hints.

import requests
from bs4 import BeautifulSoup

URL = "https://cybersapien.tech/"
page = requests.get(URL)

soup = BeautifulSoup(page.content, "html.parser")

for link in soup.find_all('a'):
    if link.get('href').startswith("https"):
        print(link.get('href'))

5). Running this code gives us many links. Among these links, obviously, we need to go to Pastebin link.

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6). Going to this link, gives us a base64 encoded text.

7). Decode it using https://www.base64decode.org/.

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This is the flag.
This confirms that we have successfully completed the challenge.

I hope, this post helped you to solve this CTF challenge easily and you must have learned something new.

Feel free to contact me for any suggestions and feedbacks. I would really appreciate those.

Thank you for reading!

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