Python impacket.krb5.types.Ticket() Examples

def toTGT(self):
        tgt_rep = AS_REP()
        tgt_rep['pvno'] = 5
        tgt_rep['msg-type'] = int(constants.ApplicationTagNumbers.AS_REP.value)
        tgt_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgt_rep['enc-part'] = None
        tgt_rep['enc-part']['etype'] = 1 
        tgt_rep['enc-part']['cipher'] = '' 
        seq_set(tgt_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        seq_set(tgt_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgt = dict()
        tgt['KDC_REP'] = encoder.encode(tgt_rep)
        tgt['cipher'] = cipher
        tgt['sessionKey'] = crypto.Key(cipher.enctype, str(self['key']['keyvalue']))
        return tgt 

def toTGS(self):
        tgs_rep = TGS_REP()
        tgs_rep['pvno'] = 5
        tgs_rep['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REP.value)
        tgs_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgs_rep['enc-part'] = None
        tgs_rep['enc-part']['etype'] = 1 
        tgs_rep['enc-part']['cipher'] = '' 
        seq_set(tgs_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        seq_set(tgs_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgs = dict()
        tgs['KDC_REP'] = encoder.encode(tgs_rep)
        tgs['cipher'] = cipher
        tgs['sessionKey'] = crypto.Key(cipher.enctype, str(self['key']['keyvalue']))
        return tgs 

def toTGT(self):
        tgt_rep = AS_REP()
        tgt_rep['pvno'] = 5
        tgt_rep['msg-type'] = int(constants.ApplicationTagNumbers.AP_REP.value)
        tgt_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgt_rep['enc-part'] = None
        tgt_rep['enc-part']['etype'] = 1 
        tgt_rep['enc-part']['cipher'] = '' 
        seq_set(tgt_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        seq_set(tgt_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgt = dict()
        tgt['KDC_REP'] = encoder.encode(tgt_rep)
        tgt['cipher'] = cipher
        tgt['sessionKey'] = crypto.Key(cipher.enctype, str(self['key']['keyvalue']))
        return tgt 

def prettyPrint(self, indent=''):
        print "%sClient: %s" % (indent, self.header['client'].prettyPrint())
        print "%sServer: %s" % (indent, self.header['server'].prettyPrint())
        print "%s%s" % (indent, self.header['key'].prettyPrint())
        print "%sTimes: " % indent
        self.header['time'].prettyPrint('\t\t')
        print "%sSubKey: %s" % (indent, self.header['is_skey'])
        print "%sFlags: 0x%x" % (indent, self.header['tktflags'])
        print "%sAddresses: %d" % (indent, self.header['num_address'])
        for address in self.addresses:
            address.prettyPrint('\t\t')
        print "%sAuth Data: %d" % (indent, len(self.authData))
        for ad in self.authData:
            ad.prettyPrint('\t\t')
        print "%sTicket: %s" % (indent, self.ticket.prettyPrint())
        print "%sSecond Ticket: %s" % (indent, self.secondTicket.prettyPrint()) 

def prettyPrint(self, indent=''):
        print "%sClient: %s" % (indent, self.header['client'].prettyPrint())
        print "%sServer: %s" % (indent, self.header['server'].prettyPrint())
        print "%s%s" % (indent, self.header['key'].prettyPrint())
        print "%sTimes: " % indent
        self.header['time'].prettyPrint('\t\t')
        print "%sSubKey: %s" % (indent, self.header['is_skey'])
        print "%sFlags: 0x%x" % (indent, self.header['tktflags'])
        print "%sAddresses: %d" % (indent, self.header['num_address'])
        for address in self.addresses:
            address.prettyPrint('\t\t')
        print "%sAuth Data: %d" % (indent, len(self.authData))
        for ad in self.authData:
            ad.prettyPrint('\t\t')
        print "%sTicket: %s" % (indent, self.ticket.prettyPrint())
        print "%sSecond Ticket: %s" % (indent, self.secondTicket.prettyPrint()) 

def toTGT(self):
        tgt_rep = AS_REP()
        tgt_rep['pvno'] = 5
        tgt_rep['msg-type'] = int(constants.ApplicationTagNumbers.AS_REP.value)
        tgt_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgt_rep['enc-part'] = noValue
        tgt_rep['enc-part']['etype'] = 1
        tgt_rep['enc-part']['cipher'] = '' 
        seq_set(tgt_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        seq_set(tgt_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgt = dict()
        tgt['KDC_REP'] = encoder.encode(tgt_rep)
        tgt['cipher'] = cipher
        tgt['sessionKey'] = crypto.Key(cipher.enctype, str(self['key']['keyvalue']))
        return tgt 

def toTGT(self):
        tgt_rep = AS_REP()
        tgt_rep['pvno'] = 5
        tgt_rep['msg-type'] = int(constants.ApplicationTagNumbers.AS_REP.value)
        tgt_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgt_rep['enc-part'] = noValue
        tgt_rep['enc-part']['etype'] = 1
        tgt_rep['enc-part']['cipher'] = '' 
        seq_set(tgt_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        seq_set(tgt_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgt = dict()
        tgt['KDC_REP'] = encoder.encode(tgt_rep)
        tgt['cipher'] = cipher
        tgt['sessionKey'] = crypto.Key(cipher.enctype, self['key']['keyvalue'])
        return tgt 

def prettyPrint(self, indent=''):
        print(("%sClient: %s" % (indent, self.header['client'].prettyPrint())))
        print(("%sServer: %s" % (indent, self.header['server'].prettyPrint())))
        print(("%s%s" % (indent, self.header['key'].prettyPrint())))
        print(("%sTimes: " % indent))
        self.header['time'].prettyPrint('\t\t')
        print(("%sSubKey: %s" % (indent, self.header['is_skey'])))
        print(("%sFlags: 0x%x" % (indent, self.header['tktflags'])))
        print(("%sAddresses: %d" % (indent, self.header['num_address'])))
        for address in self.addresses:
            address.prettyPrint('\t\t')
        print(("%sAuth Data: %d" % (indent, len(self.authData))))
        for ad in self.authData:
            ad.prettyPrint('\t\t')
        print(("%sTicket: %s" % (indent, self.ticket.prettyPrint())))
        print(("%sSecond Ticket: %s" % (indent, self.secondTicket.prettyPrint()))) 

def prettyPrint(self, indent=''):
        print "%sClient: %s" % (indent, self.header['client'].prettyPrint())
        print "%sServer: %s" % (indent, self.header['server'].prettyPrint())
        print "%s%s" % (indent, self.header['key'].prettyPrint())
        print "%sTimes: " % indent
        self.header['time'].prettyPrint('\t\t')
        print "%sSubKey: %s" % (indent, self.header['is_skey'])
        print "%sFlags: 0x%x" % (indent, self.header['tktflags'])
        print "%sAddresses: %d" % (indent, self.header['num_address'])
        for address in self.addresses:
            address.prettyPrint('\t\t')
        print "%sAuth Data: %d" % (indent, len(self.authData))
        for ad in self.authData:
            ad.prettyPrint('\t\t')
        print "%sTicket: %s" % (indent, self.ticket.prettyPrint())
        print "%sSecond Ticket: %s" % (indent, self.secondTicket.prettyPrint()) 

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 toTGS(self, newSPN=None):
        tgs_rep = TGS_REP()
        tgs_rep['pvno'] = 5
        tgs_rep['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REP.value)
        tgs_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgs_rep['enc-part'] = noValue
        tgs_rep['enc-part']['etype'] = 1
        tgs_rep['enc-part']['cipher'] = '' 
        seq_set(tgs_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        if newSPN is not None:
            if newSPN.upper() != str(ticket.service_principal).upper():
                LOG.debug('Changing sname from %s to %s and hoping for the best' % (ticket.service_principal, newSPN) )
                ticket.service_principal = types.Principal(newSPN, type=int(ticket.service_principal.type))
        seq_set(tgs_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgs = dict()
        tgs['KDC_REP'] = encoder.encode(tgs_rep)
        tgs['cipher'] = cipher
        tgs['sessionKey'] = crypto.Key(cipher.enctype, self['key']['keyvalue'])
        return tgs 

def kirbi2ccache(kirbifile, ccachefile):
    with open(kirbifile, 'rb') as infile:
        data = infile.read()
    creds = decoder.decode(data, asn1Spec=KRB_CRED())[0]
    # This shouldn't be encrypted normally
    if creds['enc-part']['etype'] != 0:
        raise Exception('Ticket info is encrypted with cipher other than null')
    enc_part = decoder.decode(creds['enc-part']['cipher'], asn1Spec=EncKrbCredPart())[0]
    tinfo = enc_part['ticket-info']
    ccache = KrbCredCCache()
    # Enumerate all
    for i, tinfo in enumerate(tinfo):
        ccache.fromKrbCredTicket(creds['tickets'][i], tinfo)
    ccache.saveFile(ccachefile) 

def toTGS(self, newSPN=None):
        tgs_rep = TGS_REP()
        tgs_rep['pvno'] = 5
        tgs_rep['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REP.value)
        tgs_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgs_rep['enc-part'] = noValue
        tgs_rep['enc-part']['etype'] = 1
        tgs_rep['enc-part']['cipher'] = '' 
        seq_set(tgs_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        if newSPN is not None:
            if newSPN.upper() != str(ticket.service_principal).upper():
                LOG.debug('Changing sname from %s to %s and hoping for the best' % (ticket.service_principal, newSPN) )
                ticket.service_principal = types.Principal(newSPN, type=int(ticket.service_principal.type))
        seq_set(tgs_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgs = dict()
        tgs['KDC_REP'] = encoder.encode(tgs_rep)
        tgs['cipher'] = cipher
        tgs['sessionKey'] = crypto.Key(cipher.enctype, str(self['key']['keyvalue']))
        return tgs 

def toTGS(self, newSPN=None):
        tgs_rep = TGS_REP()
        tgs_rep['pvno'] = 5
        tgs_rep['msg-type'] = int(constants.ApplicationTagNumbers.TGS_REP.value)
        tgs_rep['crealm'] = self['server'].realm['data']

        # Fake EncryptedData
        tgs_rep['enc-part'] = None
        tgs_rep['enc-part']['etype'] = 1 
        tgs_rep['enc-part']['cipher'] = '' 
        seq_set(tgs_rep, 'cname', self['client'].toPrincipal().components_to_asn1)
        ticket = types.Ticket()
        ticket.from_asn1(self.ticket['data'])
        if newSPN is not None:
            if newSPN.upper() != str(ticket.service_principal).upper():
                LOG.debug('Changing sname from %s to %s and hoping for the best' % (ticket.service_principal, newSPN) )
                ticket.service_principal = types.Principal(newSPN, type=int(ticket.service_principal.type))
        seq_set(tgs_rep,'ticket', ticket.to_asn1)

        cipher = crypto._enctype_table[self['key']['keytype']]()

        tgs = dict()
        tgs['KDC_REP'] = encoder.encode(tgs_rep)
        tgs['cipher'] = cipher
        tgs['sessionKey'] = crypto.Key(cipher.enctype, str(self['key']['keyvalue']))
        return tgs 

def fromTGS(self, tgs, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = '\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGS = decoder.decode(tgs, asn1Spec = TGS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGS, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGS['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGS['enc-part']['etype']]

        # Key Usage 8
        # TGS-REP encrypted part (includes application session
        # key), encrypted with the TGS session key (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 8, str(cipherText))

        encTGSRepPart = decoder.decode(plainText, asn1Spec = EncTGSRepPart())[0]

        credential = Credential()
        server = types.Principal()
        server.from_asn1(encTGSRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0 

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encTGSRepPart['key']['keytype'])
        credential['key']['keyvalue'] = str(encTGSRepPart['key']['keyvalue'])
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['renew-till'])) 

        flags = self.reverseFlags(encTGSRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0

        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGS['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = ''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential) 

def fromTGT(self, tgt, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = '\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGT, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGT['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGT['enc-part']['etype']]

        # Key Usage 3
        # AS-REP encrypted part (includes TGS session key or
        # application session key), encrypted with the client key
        # (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 3, str(cipherText))

        encASRepPart = decoder.decode(plainText, asn1Spec = EncASRepPart())[0]

        credential = Credential()
        server = types.Principal()
        server.from_asn1(encASRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encASRepPart['key']['keytype'])
        credential['key']['keyvalue'] = str(encASRepPart['key']['keyvalue'])
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['renew-till'])) 

        flags = self.reverseFlags(encASRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0
        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGT['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = ''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential) 

def fromTGT(self, tgt, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = b'\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGT, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGT['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGT['enc-part']['etype']]

        # Key Usage 3
        # AS-REP encrypted part (includes TGS session key or
        # application session key), encrypted with the client key
        # (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 3, cipherText)

        encASRepPart = decoder.decode(plainText, asn1Spec = EncASRepPart())[0]
        credential = Credential()
        server = types.Principal()
        server.from_asn1(encASRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encASRepPart['key']['keytype'])
        credential['key']['keyvalue'] = encASRepPart['key']['keyvalue'].asOctets()
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['renew-till']))

        flags = self.reverseFlags(encASRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0
        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGT['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = b''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential) 

def fromTGS(self, tgs, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = b'\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGS = decoder.decode(tgs, asn1Spec = TGS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGS, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGS['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGS['enc-part']['etype']]

        # Key Usage 8
        # TGS-REP encrypted part (includes application session
        # key), encrypted with the TGS session key (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 8, cipherText)

        encTGSRepPart = decoder.decode(plainText, asn1Spec = EncTGSRepPart())[0]

        credential = Credential()
        server = types.Principal()
        server.from_asn1(encTGSRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0 

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encTGSRepPart['key']['keytype'])
        credential['key']['keyvalue'] = encTGSRepPart['key']['keyvalue'].asOctets()
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['renew-till'])) 

        flags = self.reverseFlags(encTGSRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0

        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGS['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = b''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential) 

def fromTGS(self, tgs, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = '\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGS = decoder.decode(tgs, asn1Spec = TGS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGS, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGS['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGS['enc-part']['etype']]

        # Key Usage 8
        # TGS-REP encrypted part (includes application session
        # key), encrypted with the TGS session key (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 8, str(cipherText))

        encTGSRepPart = decoder.decode(plainText, asn1Spec = EncTGSRepPart())[0]

        credential = Credential()
        server = types.Principal()
        server.from_asn1(encTGSRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0 

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encTGSRepPart['key']['keytype'])
        credential['key']['keyvalue'] = str(encTGSRepPart['key']['keyvalue'])
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['renew-till'])) 

        flags = self.reverseFlags(encTGSRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0

        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGS['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = ''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential) 

def fromTGT(self, tgt, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = '\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGT, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGT['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGT['enc-part']['etype']]

        # Key Usage 3
        # AS-REP encrypted part (includes TGS session key or
        # application session key), encrypted with the client key
        # (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 3, str(cipherText))

        encASRepPart = decoder.decode(plainText, asn1Spec = EncASRepPart())[0]

        credential = Credential()
        server = types.Principal()
        server.from_asn1(encASRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encASRepPart['key']['keytype'])
        credential['key']['keyvalue'] = str(encASRepPart['key']['keyvalue'])
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['renew-till'])) 

        flags = self.reverseFlags(encASRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0
        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGT['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = ''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential) 

def fromTGT(self, tgt, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = '\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGT = decoder.decode(tgt, asn1Spec = AS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGT, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGT['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGT['enc-part']['etype']]

        # Key Usage 3
        # AS-REP encrypted part (includes TGS session key or
        # application session key), encrypted with the client key
        # (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 3, str(cipherText))

        encASRepPart = decoder.decode(plainText, asn1Spec = EncASRepPart())[0]

        credential = Credential()
        server = types.Principal()
        server.from_asn1(encASRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encASRepPart['key']['keytype'])
        credential['key']['keyvalue'] = str(encASRepPart['key']['keyvalue'])
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encASRepPart['renew-till'])) 

        flags = self.reverseFlags(encASRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0
        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGT['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = ''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential) 

def fromTGS(self, tgs, oldSessionKey, sessionKey):
        self.headers = []
        header = Header()
        header['tag'] = 1
        header['taglen'] = 8
        header['tagdata'] = '\xff\xff\xff\xff\x00\x00\x00\x00'
        self.headers.append(header)

        decodedTGS = decoder.decode(tgs, asn1Spec = TGS_REP())[0]

        tmpPrincipal = types.Principal()
        tmpPrincipal.from_asn1(decodedTGS, 'crealm', 'cname')
        self.principal = Principal()
        self.principal.fromPrincipal(tmpPrincipal)

        # Now let's add the credential
        cipherText = decodedTGS['enc-part']['cipher']

        cipher = crypto._enctype_table[decodedTGS['enc-part']['etype']]

        # Key Usage 8
        # TGS-REP encrypted part (includes application session
        # key), encrypted with the TGS session key (Section 5.4.2)
        plainText = cipher.decrypt(oldSessionKey, 8, str(cipherText))

        encTGSRepPart = decoder.decode(plainText, asn1Spec = EncTGSRepPart())[0]

        credential = Credential()
        server = types.Principal()
        server.from_asn1(encTGSRepPart, 'srealm', 'sname')
        tmpServer = Principal()
        tmpServer.fromPrincipal(server)
        
        credential['client'] = self.principal
        credential['server'] = tmpServer
        credential['is_skey'] = 0 

        credential['key'] = KeyBlock()
        credential['key']['keytype'] = int(encTGSRepPart['key']['keytype'])
        credential['key']['keyvalue'] = str(encTGSRepPart['key']['keyvalue'])
        credential['key']['keylen'] = len(credential['key']['keyvalue'])

        credential['time'] = Times()
        credential['time']['authtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['authtime']))
        credential['time']['starttime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['starttime'])) 
        credential['time']['endtime'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['endtime']))
        credential['time']['renew_till'] = self.toTimeStamp(types.KerberosTime.from_asn1(encTGSRepPart['renew-till'])) 

        flags = self.reverseFlags(encTGSRepPart['flags'])
        credential['tktflags'] = flags

        credential['num_address'] = 0

        credential.ticket = CountedOctetString()
        credential.ticket['data'] = encoder.encode(decodedTGS['ticket'].clone(tagSet=Ticket.tagSet, cloneValueFlag=True))
        credential.ticket['length'] = len(credential.ticket['data'])
        credential.secondTicket = CountedOctetString()
        credential.secondTicket['data'] = ''
        credential.secondTicket['length'] = 0
        self.credentials.append(credential)