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======================================================================Challenge Description
Can you beat the odds, can you become the very best?
Challenge Overview
This challenge is pretty simple we got a web page where we have a code editor. We need to create a script that will addition the input given.
****************************************************************
* *
* *
* .-""""-. *
* / \ \ *
* | .'--. | *
* | /_ _`| *
* \( a \ a ) *
* | > | *
* |\ = / *
* | \___/| *
* ___/: :\__ *
* /` < `\ /` > `\ *
* / `\ |__| /` \ *
* ; [MD] \| |/ |I! ; *
* | | | |"""| | *
* | | \ / \___/ | *
* *
****************************************************************Understanding the Challenge
Automation Script
python
import itertools
from pwn import *
context.log_level = "error"
HOST = "94.237.62.184"
PORT = 36734
class Log:
def __init__(self):
self.GREEN = "\033[32m"
self.WHITE = "\033[39m"
self.CYAN = "\033[36m"
self.BG_RED = "\033[41m"
self.DEFAULT_BG = "\033[49m"
self.RESET = "\033[0m"
self.BOLD = "\033[1m"
pass
def error(self, message, bold=False):
print(self.format_message("ERROR", self.BG_RED, message, bold))
def info(self, message, bold=False):
print(self.format_message("INFO", self.GREEN, message, bold))
def warning(self, message, bold=False):
print(self.format_message("WARNING", self.CYAN, message, bold))
def format_message(self, level, color, message, bold):
bold_format = self.BOLD if bold else ""
return f"{self.get_time()} {bold_format}{color}{level}{self.WHITE}{self.DEFAULT_BG} {message}{self.RESET}"
def get_time(self):
return f"[{self.CYAN}{time.strftime("%H:%M:%S")}{self.WHITE}]"
LOG = Log()
def send_and_receive(conn, prompt, message):
conn.recvuntil(prompt.encode())
conn.sendline(message.encode())
def extract_mac_address(conn):
while True:
line = conn.recvline().decode().strip()
match = re.search(r"Mac Address:\s*([a-f0-9:]+)", line, re.IGNORECASE)
if match:
return match.group(1)
def lcg(seed, a=1664525, c=1013904223, m=2 ** 32):
return (a * seed + c) % m
def generate_ids(seed):
random.seed(seed)
tid = random.randint(0, 65535)
sid = random.randint(0, 65535)
return tid, sid
def generate_poketmon(seed, tid, sid):
random.seed(seed)
stats = {
"HP": random.randint(20, 31),
"Attack": random.randint(20, 31),
"Defense": random.randint(20, 31),
"Speed": random.randint(20, 31),
"Special Attack": random.randint(20, 31),
"Special Defense": random.randint(20, 31)
}
natures = ["Adamant", "Bashful", "Bold", "Brave", "Calm", "Careful", "Docile", "Gentle", "Hardy", "Hasty", "Impish",
"Jolly", "Lax", "Lonely", "Mild", "Modest", "Naive", "Naughty", "Quiet", "Quirky", "Rash", "Relaxed",
"Sassy", "Serious", "Timid"]
nature = random.choice(natures)
pid = random.randint(0, 2 ** 32 - 1)
shiny_value = ((tid ^ sid) ^ (pid & 0xFFFF) ^ (pid >> 16))
is_shiny = shiny_value < 8
return is_shiny
def generate_time_to_wait(device_mac):
time_passed = 0
while True:
system_time = 0
dialog_time = system_time + time_passed
formatted_time = int(dialog_time)
initial_seed = int(formatted_time + int(device_mac.replace(":", ""), 16))
seed = lcg(initial_seed)
tid, sid = generate_ids(seed)
for i in range(3):
poketmon = generate_poketmon(seed + i, tid, sid)
if poketmon:
return time_passed, str(i + 1)
time_passed = time_passed + 1
def automate_interaction(conn, shiny_time, choice):
LOG.info("Starting the interaction with the Poketmon game")
conn.recvuntil(b"First, what is your name?")
LOG.info(f"Waiting for {shiny_time} seconds to capture the shiny Poketmon")
time.sleep(shiny_time - 16)
player_name = "pwn"
send_and_receive(conn, "Enter your name: ", player_name)
conn.recvuntil(b"You can choose one of these three Poketmon.")
send_and_receive(conn, "Choose your starter Poketmon (1, 2, or 3): ", choice)
LOG.info(f"Selected the starter Poketmon: {choice}")
while True:
response = conn.recvline()
if b"Congratulations! You have obtained a shiny Poketmon!" in response:
conn.recvuntil(b"HTB{")
flag = conn.recvuntil(b"}").decode()
LOG.info("Captured flag: HTB{" + flag)
break
elif b"Good luck on your adventure!" in response:
LOG.warning("No shiny Poketmon found.")
break
def searching_for_shiny_pokemon():
def loader():
for c in itertools.cycle(["|", "/", "-", "\\"]):
if done:
break
sys.stdout.write("\rLoading " + c)
sys.stdout.flush()
time.sleep(0.1)
done = False
loader_thread = threading.Thread(target=loader)
loader_thread.start()
while True:
conn = remote(HOST, PORT)
# Extract the MAC address
device_mac = extract_mac_address(conn)
# Generate the time to wait
shiny_time, choice = generate_time_to_wait(device_mac)
if shiny_time > 100 or shiny_time - 16 < 0:
conn.close()
continue
done = True
print("\033[H\033[J")
LOG.info(f"Device MAC address: {device_mac}")
LOG.info(f"Shiny Pokemon found at time: {shiny_time} seconds - Choice: {choice}")
# Automate the interaction
automate_interaction(conn, shiny_time, choice)
break
if __name__ == "__main__":
try:
searching_for_shiny_pokemon()
except KeyboardInterrupt:
LOG.error("Exiting the script...", bold=True)
exit(0)The script will connect to the server and extract the MAC address of the device. Then it will generate the time to wait to capture the shiny Poketmon. After that, it will automate the interaction with the game and capture the flag.