68 lines
1.8 KiB
Python
68 lines
1.8 KiB
Python
from hashlib import sha256
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import socketserver
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import signal
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import string
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import random
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import os
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class Task(socketserver.BaseRequestHandler):
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def _recvall(self):
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BUFF_SIZE = 2048
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data = b''
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while True:
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part = self.request.recv(BUFF_SIZE)
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data += part
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if len(part) < BUFF_SIZE:
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break
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return data.strip()
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def send(self, msg, newline=True):
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try:
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if newline:
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msg += b'\n'
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self.request.sendall(msg)
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except:
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pass
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def recv(self, prompt=b'[-] '):
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self.send(prompt, newline=False)
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return self._recvall()
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def proof_of_work(self):
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random.seed(os.urandom(8))
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proof = ''.join(
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[random.choice(string.ascii_letters+string.digits) for _ in range(20)])
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_hexdigest = sha256(proof.encode()).hexdigest()
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self.send(f"[+] sha256(XXXX+{proof[4:]}) == {_hexdigest}".encode())
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x = self.recv(prompt=b'[+] Plz tell me XXXX: ')
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if len(x) != 4 or sha256(x+proof[4:].encode()).hexdigest() != _hexdigest:
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return False
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return True
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def handle(self):
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signal.alarm(60)
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if not self.proof_of_work():
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self.send(b'[!] Wrong!')
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return
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self.send(b'here is your flag')
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self.send(flag)
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class ThreadedServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
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pass
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class ForkedServer(socketserver.ForkingMixIn, socketserver.TCPServer):
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pass
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if __name__ == "__main__":
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flag = bytes(os.getenv("FLAG"),"utf-8")
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HOST, PORT = '0.0.0.0', 10001
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server = ForkedServer((HOST, PORT), Task)
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server.allow_reuse_address = True
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print(HOST, PORT)
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server.serve_forever()
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