async def get_TGS(self, spn_user, override_etype=None, is_linux=False):
"""
Requests a TGS ticket for the specified user.
Retruns 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
"""
#construct tgs_req
logger.debug('Constructing TGS request for user %s' %
spn_user.get_formatted_pname())
now = datetime.datetime.utcnow()
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)
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
if is_linux:
ac = AuthenticatorChecksum()
ac.flags = 0
ac.channel_binding = b'\x00' * 16
chksum = {}
chksum['cksumtype'] = 0x8003
chksum['checksum'] = ac.to_bytes()
print(chksum['checksum'])
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('Constructing TGS request to server')
rep = await self.ksoc.sendrecv(req.dump())
if rep.name == 'KRB_ERROR':
raise Exception('get_TGS failed! %s' % str(rep))
logger.debug('Got TGS 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('Got valid TGS reply')
self.kerberos_TGS = tgs
return tgs, encTGSRepPart, key
async def get_TGT(self, override_etype=None, decrypt_tgt=True):
"""
decrypt_tgt: used for asreproast attacks
Steps performed:
1. Send and empty (no encrypted timestamp) AS_REQ with all the encryption types we support
2. Depending on the response (either error or AS_REP with TGT) we either send another AS_REQ with the encrypted data or return the TGT (or fail miserably)
3. PROFIT
"""
logger.debug('Generating initial TGT without authentication data')
now = datetime.datetime.utcnow()
kdc_req_body = {}
kdc_req_body['kdc-options'] = KDCOptions(
set(['forwardable', 'renewable', 'proxiable']))
kdc_req_body['cname'] = PrincipalName({
'name-type':
NAME_TYPE.PRINCIPAL.value,
'name-string': [self.usercreds.username]
})
kdc_req_body['realm'] = self.usercreds.domain.upper()
kdc_req_body['sname'] = PrincipalName({
'name-type':
NAME_TYPE.PRINCIPAL.value,
'name-string': ['krbtgt', self.usercreds.domain.upper()]
})
kdc_req_body['till'] = now + datetime.timedelta(days=1)
kdc_req_body['rtime'] = now + datetime.timedelta(days=1)
kdc_req_body['nonce'] = secrets.randbits(31)
if override_etype is None:
kdc_req_body['etype'] = self.usercreds.get_supported_enctypes()
else:
kdc_req_body['etype'] = override_etype
pa_data_1 = {}
pa_data_1['padata-type'] = int(PADATA_TYPE('PA-PAC-REQUEST'))
pa_data_1['padata-value'] = PA_PAC_REQUEST({
'include-pac': True
}).dump()
kdc_req = {}
kdc_req['pvno'] = krb5_pvno
kdc_req['msg-type'] = MESSAGE_TYPE.KRB_AS_REQ.value
kdc_req['padata'] = [pa_data_1]
kdc_req['req-body'] = KDC_REQ_BODY(kdc_req_body)
req = AS_REQ(kdc_req)
logger.debug('Sending initial TGT to %s' % self.ksoc.get_addr_str())
rep = await self.ksoc.sendrecv(req.dump())
if rep.name != 'KRB_ERROR':
#user can do kerberos auth without preauthentication!
self.kerberos_TGT = rep.native
#if we want to roast the asrep (tgt rep) part then we dont even have the proper keys to decrypt
#so we just return, the asrep can be extracted from this object anyhow
if decrypt_tgt == False:
return
self.kerberos_cipher = _enctype_table[23]
self.kerberos_cipher_type = 23
self.kerberos_key = Key(
self.kerberos_cipher.enctype,
self.usercreds.get_key_for_enctype(
EncryptionType.ARCFOUR_HMAC_MD5))
else:
if rep.native[
'error-code'] != KerberosErrorCode.KDC_ERR_PREAUTH_REQUIRED.value:
raise KerberosError(rep)
rep = rep.native
logger.debug('Got reply from server, asikg to provide auth data')
rep = await self.do_preauth(rep)
logger.debug('Got valid TGT response from server')
rep = rep.native
self.kerberos_TGT = rep
cipherText = rep['enc-part']['cipher']
temp = self.kerberos_cipher.decrypt(self.kerberos_key, 3, cipherText)
try:
self.kerberos_TGT_encpart = EncASRepPart.load(temp).native
except Exception as e:
logger.debug('EncAsRepPart load failed, is this linux?')
try:
self.kerberos_TGT_encpart = EncTGSRepPart.load(temp).native
except Exception as e:
logger.error('Failed to load decrypted part of the reply!')
raise e
self.kerberos_session_key = Key(
self.kerberos_cipher.enctype,
self.kerberos_TGT_encpart['key']['keyvalue'])
self.ccache.add_tgt(self.kerberos_TGT,
self.kerberos_TGT_encpart,
override_pp=True)
logger.debug('Got valid TGT')
return
async def S4U2self(
self,
user_to_impersonate,
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
]):
#def S4U2self(self, user_to_impersonate, spn_user, 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]):
"""
user_to_impersonate : KerberosTarget class
"""
if not self.kerberos_TGT:
logger.debug(
'S4U2self invoked, but TGT is not available! Fetching TGT...')
self.get_TGT()
supp_enc = self.usercreds.get_preferred_enctype(supp_enc_methods)
auth_package_name = 'Kerberos'
now = datetime.datetime.utcnow()
###### Calculating authenticator data
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
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()
###### Calculating checksum data
S4UByteArray = NAME_TYPE.PRINCIPAL.value.to_bytes(4,
'little',
signed=False)
S4UByteArray += user_to_impersonate.username.encode()
S4UByteArray += user_to_impersonate.domain.encode()
S4UByteArray += auth_package_name.encode()
logger.debug('S4U2self: S4UByteArray: %s' % S4UByteArray.hex())
logger.debug('S4U2self: S4UByteArray: %s' % S4UByteArray)
chksum_data = _HMACMD5.checksum(self.kerberos_session_key, 17,
S4UByteArray)
logger.debug('S4U2self: chksum_data: %s' % chksum_data.hex())
chksum = {}
chksum['cksumtype'] = int(CKSUMTYPE('HMAC_MD5'))
chksum['checksum'] = chksum_data
###### Filling out PA-FOR-USER data for impersonation
pa_for_user_enc = {}
pa_for_user_enc['userName'] = PrincipalName({
'name-type':
NAME_TYPE.PRINCIPAL.value,
'name-string':
user_to_impersonate.get_principalname()
})
pa_for_user_enc['userRealm'] = user_to_impersonate.domain
pa_for_user_enc['cksum'] = Checksum(chksum)
pa_for_user_enc['auth-package'] = auth_package_name
pa_for_user = {}
pa_for_user['padata-type'] = int(PADATA_TYPE('PA-FOR-USER'))
pa_for_user['padata-value'] = PA_FOR_USER_ENC(pa_for_user_enc).dump()
###### Constructing body
krb_tgs_body = {}
krb_tgs_body['kdc-options'] = KDCOptions(
set(['forwardable', 'renewable', 'canonicalize']))
krb_tgs_body['sname'] = PrincipalName({
'name-type':
NAME_TYPE.UNKNOWN.value,
'name-string': [self.usercreds.username]
})
krb_tgs_body['realm'] = self.usercreds.domain.upper()
krb_tgs_body['till'] = now + datetime.timedelta(days=1)
krb_tgs_body['nonce'] = secrets.randbits(31)
krb_tgs_body['etype'] = [
supp_enc.value
] #selecting according to server's preferences
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('Sending S4U2self request to server')
reply = await self.ksoc.sendrecv(req.dump())
if reply.name == 'KRB_ERROR':
if reply.native['error-code'] == 16:
logger.error(
'S4U2self: Failed to get S4U2self! Error code (16) indicates that delegation is not enabled for this account! Full error: %s'
% e)
raise Exception('S4U2self failed! %s' % str(reply))
logger.debug('Got S4U2self reply, decrypting...')
tgs = reply.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('Got valid TGS reply')
self.kerberos_TGS = tgs
return tgs, encTGSRepPart, key
async def do_preauth(self, rep):
#now getting server's supported encryption methods
supp_enc_methods = collections.OrderedDict()
for enc_method in METHOD_DATA.load(rep['e-data']).native:
data_type = PaDataType(enc_method['padata-type'])
if data_type == PaDataType.ETYPE_INFO or data_type == PaDataType.ETYPE_INFO2:
if data_type == PaDataType.ETYPE_INFO:
enc_info_list = ETYPE_INFO.load(enc_method['padata-value'])
elif data_type == PaDataType.ETYPE_INFO2:
enc_info_list = ETYPE_INFO2.load(
enc_method['padata-value'])
for enc_info in enc_info_list.native:
supp_enc_methods[EncryptionType(
enc_info['etype'])] = enc_info['salt']
logger.debug(
'Server supports encryption type %s with salt %s' %
(EncryptionType(
enc_info['etype']).name, enc_info['salt']))
logger.debug('Constructing TGT request with auth data')
#now to create an AS_REQ with encrypted timestamp for authentication
pa_data_1 = {}
pa_data_1['padata-type'] = int(PADATA_TYPE('PA-PAC-REQUEST'))
pa_data_1['padata-value'] = PA_PAC_REQUEST({
'include-pac': True
}).dump()
now = datetime.datetime.utcnow()
#creating timestamp asn1
timestamp = PA_ENC_TS_ENC({
'patimestamp': now,
'pausec': now.microsecond
}).dump()
supp_enc = self.usercreds.get_preferred_enctype(supp_enc_methods)
logger.debug('Selecting common encryption type: %s' % supp_enc.name)
self.kerberos_cipher = _enctype_table[supp_enc.value]
self.kerberos_cipher_type = supp_enc.value
if 'salt' in enc_info and enc_info['salt'] is not None:
self.server_salt = enc_info['salt'].encode()
self.kerberos_key = Key(
self.kerberos_cipher.enctype,
self.usercreds.get_key_for_enctype(supp_enc,
salt=self.server_salt))
enc_timestamp = self.kerberos_cipher.encrypt(self.kerberos_key, 1,
timestamp, None)
pa_data_2 = {}
pa_data_2['padata-type'] = int(PADATA_TYPE('ENC-TIMESTAMP'))
pa_data_2['padata-value'] = EncryptedData({
'etype': supp_enc.value,
'cipher': enc_timestamp
}).dump()
kdc_req_body = {}
kdc_req_body['kdc-options'] = KDCOptions(
set(['forwardable', 'renewable', 'proxiable']))
kdc_req_body['cname'] = PrincipalName({
'name-type':
NAME_TYPE.PRINCIPAL.value,
'name-string': [self.usercreds.username]
})
kdc_req_body['realm'] = self.usercreds.domain.upper()
kdc_req_body['sname'] = PrincipalName({
'name-type':
NAME_TYPE.PRINCIPAL.value,
'name-string': ['krbtgt', self.usercreds.domain.upper()]
})
kdc_req_body['till'] = now + datetime.timedelta(days=1)
kdc_req_body['rtime'] = now + datetime.timedelta(days=1)
kdc_req_body['nonce'] = secrets.randbits(31)
kdc_req_body['etype'] = [
supp_enc.value
] #selecting according to server's preferences
kdc_req = {}
kdc_req['pvno'] = krb5_pvno
kdc_req['msg-type'] = MESSAGE_TYPE.KRB_AS_REQ.value
kdc_req['padata'] = [pa_data_2, pa_data_1]
kdc_req['req-body'] = KDC_REQ_BODY(kdc_req_body)
req = AS_REQ(kdc_req)
logger.debug('Sending TGT request to server')
rep = await self.ksoc.sendrecv(req.dump())
if rep.name == 'KRB_ERROR':
raise Exception('Preauth failed! %s' % str(rep))
return rep
def S4U2proxy(self, s4uself_ticket, spn_user, 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]):
logger.debug('[S4U2proxy] Impersonating %s' % '/'.join(spn_user.get_principalname()))
now = datetime.datetime.now(datetime.timezone.utc)
supp_enc = self.usercreds.get_preferred_enctype(supp_enc_methods)
pa_pac_opts = {}
pa_pac_opts['padata-type'] = int(PADATA_TYPE('PA-PAC-OPTIONS'))
pa_pac_opts['padata-value'] = PA_PAC_OPTIONS({'value' : PA_PAC_OPTIONSTypes(set(['resource-based constrained delegation']))}).dump()
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_tgs_req = {}
pa_tgs_req['padata-type'] = PaDataType.TGS_REQ.value
pa_tgs_req['padata-value'] = AP_REQ(ap_req).dump()
krb_tgs_body = {}
krb_tgs_body['kdc-options'] = KDCOptions(set(['forwardable','renewable','constrained-delegation', 'canonicalize']))
krb_tgs_body['sname'] = PrincipalName({'name-type': NAME_TYPE.SRV_INST.value, 'name-string': spn_user.get_principalname()})
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'] = [supp_enc.value] #selecting according to server's preferences
krb_tgs_body['additional-tickets'] = [s4uself_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_tgs_req, pa_pac_opts]
krb_tgs_req['req-body'] = KDC_REQ_BODY(krb_tgs_body)
req = TGS_REQ(krb_tgs_req)
logger.debug('[S4U2proxy] Sending request to server')
try:
reply = self.ksoc.sendrecv(req.dump())
except KerberosError as e:
if e.errorcode.value == 16:
logger.error('S4U2proxy: Failed to get S4U2proxy! Error code (16) indicates that delegation is not enabled for this account! Full error: %s' % e)
raise e
logger.debug('[S4U2proxy] Got server reply, decrypting...')
tgs = reply.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('[S4U2proxy] Got valid TGS reply')
return tgs, encTGSRepPart, key
