def construct_apreq(self, tgs, encTGSRepPart, sessionkey, flags = None, seq_number = 0, ap_opts = [], cb_data = None):
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)
if flags is not None:
ac = AuthenticatorChecksum()
ac.flags = flags
ac.channel_binding = b'\x00'*16
if cb_data is not None:
ac.channel_binding = hashlib.md5(cb_data).digest()
chksum = {}
chksum['cksumtype'] = 0x8003
chksum['checksum'] = ac.to_bytes()
authenticator_data['cksum'] = Checksum(chksum)
authenticator_data['seq-number'] = seq_number
cipher = _enctype_table[encTGSRepPart['key']['keytype']]
authenticator_data_enc = cipher.encrypt(sessionkey, 11, Authenticator(authenticator_data).dump(), None)
ap_req = {}
ap_req['pvno'] = krb5_pvno
ap_req['msg-type'] = MESSAGE_TYPE.KRB_AP_REQ.value
ap_req['ticket'] = Ticket(tgs['ticket'])
ap_req['ap-options'] = APOptions(set(ap_opts))
ap_req['authenticator'] = EncryptedData({'etype': self.kerberos_cipher_type, 'cipher': authenticator_data_enc})
return AP_REQ(ap_req).dump()
def construct_apreq_from_ticket(ticket_data,
sessionkey,
crealm,
cname,
flags=None,
seq_number=0,
ap_opts=[],
cb_data=None):
"""
ticket: bytes of Ticket
"""
now = datetime.datetime.now(datetime.timezone.utc)
authenticator_data = {}
authenticator_data['authenticator-vno'] = krb5_pvno
authenticator_data['crealm'] = Realm(crealm)
authenticator_data['cname'] = PrincipalName({
'name-type':
NAME_TYPE.PRINCIPAL.value,
'name-string': [cname]
})
authenticator_data['cusec'] = now.microsecond
authenticator_data['ctime'] = now.replace(microsecond=0)
if flags is not None:
ac = AuthenticatorChecksum()
ac.flags = flags
ac.channel_binding = b'\x00' * 16
if cb_data is not None:
ac.channel_binding = hashlib.md5(cb_data).digest()
chksum = {}
chksum['cksumtype'] = 0x8003
chksum['checksum'] = ac.to_bytes()
authenticator_data['cksum'] = Checksum(chksum)
authenticator_data['seq-number'] = seq_number
cipher = _enctype_table[sessionkey.enctype]
authenticator_data_enc = cipher.encrypt(
sessionkey, 11,
Authenticator(authenticator_data).dump(), None)
ap_req = {}
ap_req['pvno'] = krb5_pvno
ap_req['msg-type'] = MESSAGE_TYPE.KRB_AP_REQ.value
ap_req['ticket'] = Ticket.load(ticket_data)
ap_req['ap-options'] = APOptions(set(ap_opts))
ap_req['authenticator'] = EncryptedData({
'etype':
sessionkey.enctype,
'cipher':
authenticator_data_enc
})
return AP_REQ(ap_req).dump()
def get_TGS(self, spn_user, override_etype = None, is_linux = False):
"""
Requests a TGS ticket for the specified user.
Returns the TGS ticket, end the decrpyted encTGSRepPart.
spn_user: KerberosTarget: the service user you want to get TGS for.
override_etype: None or list of etype values (int) Used mostly for kerberoasting, will override the AP_REQ supported etype values (which is derived from the TGT) to be able to recieve whatever tgs tiecket
"""
logger.debug('[getTGS] Constructing request for user %s' % spn_user.get_formatted_pname())
now = datetime.datetime.now(datetime.timezone.utc)
kdc_req_body = {}
kdc_req_body['kdc-options'] = KDCOptions(set(['forwardable','renewable','renewable_ok', 'canonicalize']))
kdc_req_body['realm'] = spn_user.domain.upper()
kdc_req_body['sname'] = PrincipalName({'name-type': NAME_TYPE.SRV_INST.value, 'name-string': spn_user.get_principalname()})
kdc_req_body['till'] = (now + datetime.timedelta(days=1)).replace(microsecond=0)
kdc_req_body['nonce'] = secrets.randbits(31)
if override_etype:
kdc_req_body['etype'] = override_etype
else:
kdc_req_body['etype'] = [self.kerberos_cipher_type]
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)
if is_linux:
ac = AuthenticatorChecksum()
ac.flags = 0
ac.channel_binding = b'\x00'*16
chksum = {}
chksum['cksumtype'] = 0x8003
chksum['checksum'] = ac.to_bytes()
authenticator_data['cksum'] = Checksum(chksum)
authenticator_data['seq-number'] = 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_1 = {}
pa_data_1['padata-type'] = PaDataType.TGS_REQ.value
pa_data_1['padata-value'] = AP_REQ(ap_req).dump()
kdc_req = {}
kdc_req['pvno'] = krb5_pvno
kdc_req['msg-type'] = MESSAGE_TYPE.KRB_TGS_REQ.value
kdc_req['padata'] = [pa_data_1]
kdc_req['req-body'] = KDC_REQ_BODY(kdc_req_body)
req = TGS_REQ(kdc_req)
logger.debug('[getTGS] Constructing request to server')
rep = self.ksoc.sendrecv(req.dump())
logger.debug('[getTGS] Got reply, decrypting...')
tgs = rep.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('[getTGS] Got valid reply')
self.kerberos_TGS = tgs
return tgs, encTGSRepPart, key
def build_apreq(self,
asrep,
session_key,
cipher,
subkey_data,
krb_finished_data,
flags=GSSAPIFlags.GSS_C_MUTUAL_FLAG
| GSSAPIFlags.GSS_C_INTEG_FLAG
| GSSAPIFlags.GSS_C_EXTENDED_ERROR_FLAG):
# TODO: https://www.ietf.org/rfc/rfc4757.txt
#subkey_data = {}
#subkey_data['keytype'] = Enctype.AES256
#subkey_data['keyvalue'] = os.urandom(32)
subkey_cipher = _enctype_table[subkey_data['keytype']]
subkey_key = Key(subkey_cipher.enctype, subkey_data['keyvalue'])
subkey_checksum = _checksum_table[
16] # ChecksumTypes.hmac_sha1_96_aes256
krb_finished_checksum_data = {}
krb_finished_checksum_data['cksumtype'] = 16
krb_finished_checksum_data['checksum'] = subkey_checksum.checksum(
subkey_key, 41, krb_finished_data)
krb_finished_data = {}
krb_finished_data['gss-mic'] = Checksum(krb_finished_checksum_data)
krb_finished = KRB_FINISHED(krb_finished_data).dump()
a = 2
extensions_data = a.to_bytes(
4, byteorder='big', signed=True) + len(krb_finished).to_bytes(
4, byteorder='big', signed=True) + krb_finished
ac = AuthenticatorChecksum()
ac.flags = flags
ac.channel_binding = b'\x00' * 16
chksum = {}
chksum['cksumtype'] = 0x8003
chksum['checksum'] = ac.to_bytes() + extensions_data
tii = LSAP_TOKEN_INFO_INTEGRITY()
tii.Flags = 1
tii.TokenIL = 0x00002000 # Medium integrity
tii.MachineID = bytes.fromhex(
'7e303fffe6bff25146addca4fbddf1b94f1634178eb4528fb2731c669ca23cde')
restriction_data = {}
restriction_data['restriction-type'] = 0
restriction_data['restriction'] = tii.to_bytes()
restriction_data = KERB_AD_RESTRICTION_ENTRY(restriction_data)
x = KERB_AD_RESTRICTION_ENTRYS([restriction_data]).dump()
restrictions = AuthorizationData([{
'ad-type': 141,
'ad-data': x
}]).dump()
now = datetime.datetime.now(datetime.timezone.utc)
authenticator_data = {}
authenticator_data['authenticator-vno'] = krb5_pvno
authenticator_data['crealm'] = Realm(asrep['crealm'])
authenticator_data['cname'] = asrep['cname']
authenticator_data['cusec'] = now.microsecond
authenticator_data['ctime'] = now.replace(microsecond=0)
authenticator_data['subkey'] = EncryptionKey(subkey_data)
authenticator_data['seq-number'] = 682437742 #??? TODO: check this!
authenticator_data['authorization-data'] = AuthorizationData([{
'ad-type':
1,
'ad-data':
restrictions
}])
authenticator_data['cksum'] = Checksum(chksum)
#print('Authenticator(authenticator_data).dump()')
#print(Authenticator(authenticator_data).dump().hex())
authenticator_data_enc = cipher.encrypt(
session_key, 11,
Authenticator(authenticator_data).dump(), None)
ap_opts = ['mutual-required']
ap_req = {}
ap_req['pvno'] = krb5_pvno
ap_req['msg-type'] = MESSAGE_TYPE.KRB_AP_REQ.value
ap_req['ticket'] = Ticket(asrep['ticket'])
ap_req['ap-options'] = APOptions(set(ap_opts))
ap_req['authenticator'] = EncryptedData({
'etype':
session_key.enctype,
'cipher':
authenticator_data_enc
})
#pprint('AP_REQ \r\n%s' % AP_REQ(ap_req).native)
#print(AP_REQ(ap_req).dump().hex())
#input()
return AP_REQ(ap_req).dump()