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 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
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
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
