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fixes, getting NT from pkinit
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SkelSec committed Aug 31, 2022
1 parent 56497fc commit d22a2b0
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2 changes: 1 addition & 1 deletion minikerberos/_version.py
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@

__version__ = "0.3.0"
__version__ = "0.3.1"
__banner__ = \
"""
# minikerberos %s
Expand Down
128 changes: 121 additions & 7 deletions minikerberos/aioclient.py
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@
PADATA_TYPE, PA_PAC_REQUEST, PA_ENC_TS_ENC, EncryptedData, krb5_pvno, KDC_REQ_BODY, \
AS_REQ, TGS_REP, KDCOptions, PrincipalName, EncASRepPart, EncTGSRepPart, PrincipalName, Realm, \
Checksum, APOptions, Authenticator, Ticket, AP_REQ, TGS_REQ, CKSUMTYPE, \
PA_FOR_USER_ENC, PA_PAC_OPTIONS, PA_PAC_OPTIONSTypes
PA_FOR_USER_ENC, PA_PAC_OPTIONS, PA_PAC_OPTIONSTypes, EncTicketPart, AD_IF_RELEVANT

from minikerberos.protocol.errors import KerberosErrorCode, KerberosError
from minikerberos.protocol.encryption import Key, _enctype_table, _HMACMD5, Enctype, _checksum_table
Expand All @@ -40,6 +40,7 @@ def __init__(self, ccred:KerberosCredential, target:KerberosTarget):
self.target = target
self.ksoc = AIOKerberosClientSocket(self.target)
self.ccache = CCACHE() if self.usercreds.ccache is None else self.usercreds.ccache
self.pkinit_tkey = None
self.kerberos_session_key = None
self.kerberos_TGT = None
self.kerberos_TGT_encpart = None
Expand Down Expand Up @@ -465,6 +466,78 @@ async def get_TGS(self, spn_user, override_etype = None, is_linux = False):
logger.debug('Got valid TGS reply')
self.kerberos_TGS = tgs
return tgs, encTGSRepPart, key

async def U2U(self, kdcopts = ['forwardable','renewable','canonicalize', 'enc-tkt-in-skey'], supp_enc_methods = [EncryptionType.DES_CBC_CRC,EncryptionType.DES_CBC_MD4,EncryptionType.DES_CBC_MD5,EncryptionType.DES3_CBC_SHA1,EncryptionType.ARCFOUR_HMAC_MD5,EncryptionType.AES256_CTS_HMAC_SHA1_96,EncryptionType.AES128_CTS_HMAC_SHA1_96]):
if not self.kerberos_TGT:
logger.debug('[U2U] TGT is not available! Fetching TGT...')
await self.get_TGT()

supp_enc = self.usercreds.get_preferred_enctype(supp_enc_methods)
now = datetime.datetime.now(datetime.timezone.utc)
authenticator_data = {}
authenticator_data['authenticator-vno'] = krb5_pvno
authenticator_data['crealm'] = Realm(self.kerberos_TGT['crealm'])
authenticator_data['cname'] = self.kerberos_TGT['cname']
authenticator_data['cusec'] = now.microsecond
authenticator_data['ctime'] = now.replace(microsecond=0)


authenticator_data_enc = self.kerberos_cipher.encrypt(self.kerberos_session_key, 7, Authenticator(authenticator_data).dump(), None)

ap_req = {}
ap_req['pvno'] = krb5_pvno
ap_req['msg-type'] = MESSAGE_TYPE.KRB_AP_REQ.value
ap_req['ap-options'] = APOptions(set())
ap_req['ticket'] = Ticket(self.kerberos_TGT['ticket'])
ap_req['authenticator'] = EncryptedData({'etype': self.kerberos_cipher_type, 'cipher': authenticator_data_enc})

pa_data_auth = {}
pa_data_auth['padata-type'] = PaDataType.TGS_REQ.value
pa_data_auth['padata-value'] = AP_REQ(ap_req).dump()


krb_tgs_body = {}
krb_tgs_body['kdc-options'] = KDCOptions(set(kdcopts))
krb_tgs_body['sname'] = PrincipalName({'name-type': NAME_TYPE.PRINCIPAL.value, 'name-string': [self.usercreds.username]})
krb_tgs_body['realm'] = self.usercreds.domain.upper()
krb_tgs_body['till'] = (now + datetime.timedelta(days=1)).replace(microsecond=0)
krb_tgs_body['nonce'] = secrets.randbits(31)
krb_tgs_body['etype'] = [23] # dunno why it must be 23?
krb_tgs_body['additional-tickets'] = [Ticket(self.kerberos_TGT['ticket'])]


krb_tgs_req = {}
krb_tgs_req['pvno'] = krb5_pvno
krb_tgs_req['msg-type'] = MESSAGE_TYPE.KRB_TGS_REQ.value
krb_tgs_req['padata'] = [pa_data_auth] #pa_for_user
krb_tgs_req['req-body'] = KDC_REQ_BODY(krb_tgs_body)



req = TGS_REQ(krb_tgs_req)
logger.debug('[U2U] Sending request to server')

reply = await self.ksoc.sendrecv(req.dump())
if reply.name == 'KRB_ERROR':
emsg = '[U2U] failed!'
if reply.native['error-code'] == 16:
emsg = '[U2U] Failed to get U2U! Error code (16) indicates that delegation is not enabled for this account!'
raise KerberosError(reply, emsg)

logger.debug('[U2U] Got reply, decrypting...')
tgs = reply.native

cipher = _enctype_table[int(tgs['ticket']['enc-part']['etype'])]
encticket = tgs['ticket']['enc-part']['cipher']
decdata = cipher.decrypt(self.kerberos_session_key, 2, encticket)
decticket = EncTicketPart.load(decdata).native

encTGSRepPart = EncTGSRepPart.load(self.kerberos_cipher.decrypt(self.kerberos_session_key, 8, tgs['enc-part']['cipher'])).native
key = Key(encTGSRepPart['key']['keytype'], encTGSRepPart['key']['keyvalue'])
self.ccache.add_tgs(tgs, encTGSRepPart)
logger.debug('[U2U] Got valid TGS reply')

return tgs, encTGSRepPart, key, decticket

#https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-sfu/6a8dfc0c-2d32-478a-929f-5f9b1b18a169
async def S4U2self(self, user_to_impersonate, spn_user = None, kdcopts = ['forwardable','renewable','canonicalize'], supp_enc_methods = [EncryptionType.DES_CBC_CRC,EncryptionType.DES_CBC_MD4,EncryptionType.DES_CBC_MD5,EncryptionType.DES3_CBC_SHA1,EncryptionType.ARCFOUR_HMAC_MD5,EncryptionType.AES256_CTS_HMAC_SHA1_96,EncryptionType.AES128_CTS_HMAC_SHA1_96]):
Expand All @@ -474,7 +547,7 @@ async def S4U2self(self, user_to_impersonate, spn_user = None, kdcopts = ['forwa

if not self.kerberos_TGT:
logger.debug('[S4U2self] TGT is not available! Fetching TGT...')
self.get_TGT()
await self.get_TGT()

supp_enc = self.usercreds.get_preferred_enctype(supp_enc_methods)
auth_package_name = 'Kerberos'
Expand All @@ -498,6 +571,7 @@ async def S4U2self(self, user_to_impersonate, spn_user = None, kdcopts = ['forwa
ap_req['ticket'] = Ticket(self.kerberos_TGT['ticket'])
ap_req['authenticator'] = EncryptedData({'etype': self.kerberos_cipher_type, 'cipher': authenticator_data_enc})


pa_data_auth = {}
pa_data_auth['padata-type'] = PaDataType.TGS_REQ.value
pa_data_auth['padata-value'] = AP_REQ(ap_req).dump()
Expand Down Expand Up @@ -770,18 +844,58 @@ def truncate_key(value, keysize):
etype = as_rep['enc-part']['etype']
cipher = _enctype_table[etype]
if etype == Enctype.AES256:
t_key = truncate_key(fullKey, 32)
self.pkinit_tkey = truncate_key(fullKey, 32)
elif etype == Enctype.AES128:
t_key = truncate_key(fullKey, 16)
self.pkinit_tkey = truncate_key(fullKey, 16)
elif etype == Enctype.RC4:
raise NotImplementedError('RC4 key truncation documentation missing. it is different from AES')
#t_key = truncate_key(fullKey, 16)
#self.pkinit_tkey = truncate_key(fullKey, 16)


key = Key(cipher.enctype, t_key)
key = Key(cipher.enctype, self.pkinit_tkey)
enc_data = as_rep['enc-part']['cipher']
dec_data = cipher.decrypt(key, 3, enc_data)
encasrep = EncASRepPart.load(dec_data).native
cipher = _enctype_table[ int(encasrep['key']['keytype'])]
session_key = Key(cipher.enctype, encasrep['key']['keyvalue'])
return encasrep, session_key, cipher
return encasrep, session_key, cipher


def get_NT_from_PAC(self, decticket:EncTicketPart, truncated_keydata=None):
from minikerberos.protocol.external.rpcrt import TypeSerialization1
from minikerberos.protocol.external.pac import PACTYPE, PAC_INFO_BUFFER, \
PAC_CREDENTIAL_INFO, PAC_CREDENTIAL_DATA, NTLM_SUPPLEMENTAL_CREDENTIAL


adIfRelevant = AD_IF_RELEVANT.load(decticket['authorization-data'][0]['ad-data'])
if truncated_keydata is None:
truncated_keydata = self.pkinit_tkey
if truncated_keydata is None:
raise Exception("Missing tkey! Is this a PKINIT session?")
key = Key(18, truncated_keydata)
pacType = PACTYPE(adIfRelevant.native[0]['ad-data'])
buff = pacType['Buffers']
creds = []
for bufferN in range(pacType['cBuffers']):
infoBuffer = PAC_INFO_BUFFER(buff)
data = pacType['Buffers'][infoBuffer['Offset']-8:][:infoBuffer['cbBufferSize']]
logger.debug("TYPE 0x%x" % infoBuffer['ulType'])
if infoBuffer['ulType'] == 2:
credinfo = PAC_CREDENTIAL_INFO(data)
newCipher = _enctype_table[credinfo['EncryptionType']]

out = newCipher.decrypt(key, 16, credinfo['SerializedData'])
type1 = TypeSerialization1(out)
# I'm skipping here 4 bytes with its the ReferentID for the pointer
newdata = out[len(type1)+4:]
pcc = PAC_CREDENTIAL_DATA(newdata)
for cred in pcc['Credentials']:
credstruct = NTLM_SUPPLEMENTAL_CREDENTIAL(b''.join(cred['Credentials']))
if credstruct['NtPassword'] != b'\x00'*16:
creds.append(('NT', credstruct['NtPassword'].hex()))
if credstruct['LmPassword'] != b'\x00'*16:
creds.append(('LM', credstruct['LmPassword'].hex()))

buff = buff[len(infoBuffer):]

return creds
123 changes: 117 additions & 6 deletions minikerberos/client.py
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@
PADATA_TYPE, PA_PAC_REQUEST, PA_ENC_TS_ENC, EncryptedData, krb5_pvno, KDC_REQ_BODY, \
AS_REQ, TGS_REP, KDCOptions, PrincipalName, EncASRepPart, EncTGSRepPart, PrincipalName, Realm, \
Checksum, APOptions, Authenticator, Ticket, AP_REQ, TGS_REQ, CKSUMTYPE, \
PA_FOR_USER_ENC, PA_PAC_OPTIONS, PA_PAC_OPTIONSTypes
PA_FOR_USER_ENC, PA_PAC_OPTIONS, PA_PAC_OPTIONSTypes, EncTicketPart, AD_IF_RELEVANT

from minikerberos.protocol.errors import KerberosErrorCode, KerberosError
from minikerberos.protocol.encryption import Key, _enctype_table, _HMACMD5, Enctype
Expand All @@ -42,6 +42,7 @@ def __init__(self, ccred, target, ccache = None):
self.kerberos_cipher_type = None
self.kerberos_key = None
self.server_salt = None
self.pkinit_tkey = None

@staticmethod
def from_tgt(target, tgt, key):
Expand Down Expand Up @@ -699,18 +700,128 @@ def truncate_key(value, keysize):
etype = as_rep['enc-part']['etype']
cipher = _enctype_table[etype]
if etype == Enctype.AES256:
t_key = truncate_key(fullKey, 32)
self.pkinit_tkey = truncate_key(fullKey, 32)
elif etype == Enctype.AES128:
t_key = truncate_key(fullKey, 16)
self.pkinit_tkey = truncate_key(fullKey, 16)
elif etype == Enctype.RC4:
raise NotImplementedError('RC4 key truncation documentation missing. it is different from AES')
#t_key = truncate_key(fullKey, 16)
#self.pkinit_tkey = truncate_key(fullKey, 16)


key = Key(cipher.enctype, t_key)
key = Key(cipher.enctype, self.pkinit_tkey)
enc_data = as_rep['enc-part']['cipher']
dec_data = cipher.decrypt(key, 3, enc_data)
encasrep = EncASRepPart.load(dec_data).native
cipher = _enctype_table[ int(encasrep['key']['keytype'])]
session_key = Key(cipher.enctype, encasrep['key']['keyvalue'])
return encasrep, session_key, cipher
return encasrep, session_key, cipher

def U2U(self, kdcopts = ['forwardable','renewable','canonicalize', 'enc-tkt-in-skey']):
if not self.kerberos_TGT:
logger.debug('[U2U] TGT is not available! Fetching TGT...')
self.get_TGT()

now = datetime.datetime.now(datetime.timezone.utc)
authenticator_data = {}
authenticator_data['authenticator-vno'] = krb5_pvno
authenticator_data['crealm'] = Realm(self.kerberos_TGT['crealm'])
authenticator_data['cname'] = self.kerberos_TGT['cname']
authenticator_data['cusec'] = now.microsecond
authenticator_data['ctime'] = now.replace(microsecond=0)


authenticator_data_enc = self.kerberos_cipher.encrypt(self.kerberos_session_key, 7, Authenticator(authenticator_data).dump(), None)

ap_req = {}
ap_req['pvno'] = krb5_pvno
ap_req['msg-type'] = MESSAGE_TYPE.KRB_AP_REQ.value
ap_req['ap-options'] = APOptions(set())
ap_req['ticket'] = Ticket(self.kerberos_TGT['ticket'])
ap_req['authenticator'] = EncryptedData({'etype': self.kerberos_cipher_type, 'cipher': authenticator_data_enc})

pa_data_auth = {}
pa_data_auth['padata-type'] = PaDataType.TGS_REQ.value
pa_data_auth['padata-value'] = AP_REQ(ap_req).dump()


krb_tgs_body = {}
krb_tgs_body['kdc-options'] = KDCOptions(set(kdcopts))
krb_tgs_body['sname'] = PrincipalName({'name-type': NAME_TYPE.PRINCIPAL.value, 'name-string': [self.usercreds.username]})
krb_tgs_body['realm'] = self.usercreds.domain.upper()
krb_tgs_body['till'] = (now + datetime.timedelta(days=1)).replace(microsecond=0)
krb_tgs_body['nonce'] = secrets.randbits(31)
krb_tgs_body['etype'] = [23] # dunno why it must be 23?
krb_tgs_body['additional-tickets'] = [Ticket(self.kerberos_TGT['ticket'])]


krb_tgs_req = {}
krb_tgs_req['pvno'] = krb5_pvno
krb_tgs_req['msg-type'] = MESSAGE_TYPE.KRB_TGS_REQ.value
krb_tgs_req['padata'] = [pa_data_auth] #pa_for_user
krb_tgs_req['req-body'] = KDC_REQ_BODY(krb_tgs_body)



req = TGS_REQ(krb_tgs_req)
logger.debug('[U2U] Sending request to server')

reply = self.ksoc.sendrecv(req.dump())
if reply.name == 'KRB_ERROR':
emsg = '[U2U] failed!'
if reply.native['error-code'] == 16:
emsg = '[U2U] Failed to get U2U! Error code (16) indicates that delegation is not enabled for this account!'
raise KerberosError(reply, emsg)

logger.debug('[U2U] Got reply, decrypting...')
tgs = reply.native

cipher = _enctype_table[int(tgs['ticket']['enc-part']['etype'])]
encticket = tgs['ticket']['enc-part']['cipher']
decdata = cipher.decrypt(self.kerberos_session_key, 2, encticket)
decticket = EncTicketPart.load(decdata).native

encTGSRepPart = EncTGSRepPart.load(self.kerberos_cipher.decrypt(self.kerberos_session_key, 8, tgs['enc-part']['cipher'])).native
key = Key(encTGSRepPart['key']['keytype'], encTGSRepPart['key']['keyvalue'])
self.ccache.add_tgs(tgs, encTGSRepPart)
logger.debug('[U2U] Got valid TGS reply')

return tgs, encTGSRepPart, key, decticket

def get_NT_from_PAC(self, decticket:EncTicketPart, truncated_keydata=None):
from minikerberos.protocol.external.rpcrt import TypeSerialization1
from minikerberos.protocol.external.pac import PACTYPE, PAC_INFO_BUFFER, \
PAC_CREDENTIAL_INFO, PAC_CREDENTIAL_DATA, NTLM_SUPPLEMENTAL_CREDENTIAL


adIfRelevant = AD_IF_RELEVANT.load(decticket['authorization-data'][0]['ad-data'])
if truncated_keydata is None:
truncated_keydata = self.pkinit_tkey
if truncated_keydata is None:
raise Exception("Missing tkey! Is this a PKINIT session?")
key = Key(18, truncated_keydata)
pacType = PACTYPE(adIfRelevant.native[0]['ad-data'])
buff = pacType['Buffers']
creds = []
for bufferN in range(pacType['cBuffers']):
infoBuffer = PAC_INFO_BUFFER(buff)
data = pacType['Buffers'][infoBuffer['Offset']-8:][:infoBuffer['cbBufferSize']]
logger.debug("TYPE 0x%x" % infoBuffer['ulType'])
if infoBuffer['ulType'] == 2:
credinfo = PAC_CREDENTIAL_INFO(data)
newCipher = _enctype_table[credinfo['EncryptionType']]

out = newCipher.decrypt(key, 16, credinfo['SerializedData'])
type1 = TypeSerialization1(out)
# I'm skipping here 4 bytes with its the ReferentID for the pointer
newdata = out[len(type1)+4:]
pcc = PAC_CREDENTIAL_DATA(newdata)
for cred in pcc['Credentials']:
credstruct = NTLM_SUPPLEMENTAL_CREDENTIAL(b''.join(cred['Credentials']))
if credstruct['NtPassword'] != b'\x00'*16:
creds.append(('NT', credstruct['NtPassword'].hex()))
if credstruct['LmPassword'] != b'\x00'*16:
creds.append(('LM', credstruct['LmPassword'].hex()))

buff = buff[len(infoBuffer):]

return creds
7 changes: 2 additions & 5 deletions minikerberos/common/constants.py
View file
Original file line number Diff line number Diff line change
@@ -1,9 +1,5 @@
import enum

class KerberosSocketType(enum.Enum):
UDP = enum.auto()
TCP = enum.auto()

class KerberosSecretType(enum.Enum):
PASSWORD = 'PASSWORD'
PW = 'PW'
Expand All @@ -20,4 +16,5 @@ class KerberosSecretType(enum.Enum):
KEYTAB = 'KEYTAB'
KIRBI = 'KIRBI'
PFX = 'PFX'
PEM = 'PEM'
PEM = 'PEM'
PFXSTR = 'PFXSTR'
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