Word Wide Web

Description

Isn’t the Word Wide Web a fascinating place to be in? Words.. so many words.. all linked… NOTE: The flag doesn’t have a wrapper. It needs to be wrapped with curly brackets and please put CTF in front of the curly brackets.

Link http://web.chal.csaw.io:5010/

Steps

when opening the URL you are greeted with a link to another page

which redirects us to another page full of highlighted words in <a> tags but not all of them have an href which can be observed through the browser inspector

The challenge can be solved by clicking on the links till you reach the flag but writing a python script is easier

Solution

from os import link
import requests
import json
from bs4 import BeautifulSoup

req = requests.Session()
mainlink = "<http://web.chal.csaw.io:5010>"
links = ['/']

def getpage():
    global mainlink, links
    subdir=links.pop()
    links = []
    result = req.get(mainlink+subdir)
    print(f'getting {mainlink+subdir}')
    src = result.content
    soup = BeautifulSoup(src, "lxml")
    a_links = soup.find_all("a")
    links.extend([link.get("href") for link in a_links if link != ""])
    links = [l for l in links if l != None]
    with open("links.json", "w") as jsonfile:
        jsonfile.write(json.dumps(links))
    if links:
        getpage()
    else: print(result.content.decode())

getpage()

Flag

CTF{w0rdS_4R3_4mAz1nG_r1ght}