Files
rdpy/rdpy/core/nla/ntlm.py
2020-04-14 21:56:46 +02:00

635 lines
24 KiB
Python

#
# Copyright (c) 2014-2015 Sylvain Peyrefitte
#
# This file is part of rdpy.
#
# rdpy is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
"""
@summary: NTLM Authentication
@see: https://msdn.microsoft.com/en-us/library/cc236621.aspx
"""
import hashlib, hmac, struct, datetime
from rdpy.core.nla import sspi
import rdpy.security.pyDes as pyDes
import rdpy.security.rc4 as rc4
from rdpy.security.rsa_wrapper import random
from rdpy.model.type import CompositeType, CallableValue, String, UInt8, UInt16Le, UInt24Le, UInt32Le, sizeof, Stream
from rdpy.model import filetimes, error
class MajorVersion(object):
"""
@see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
@see: https://msdn.microsoft.com/en-us/library/a211d894-21bc-4b8b-86ba-b83d0c167b00#id29
"""
WINDOWS_MAJOR_VERSION_5 = 0x05
WINDOWS_MAJOR_VERSION_6 = 0x06
class MinorVersion(object):
"""
@see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
@see: https://msdn.microsoft.com/en-us/library/a211d894-21bc-4b8b-86ba-b83d0c167b00#id30
"""
WINDOWS_MINOR_VERSION_0 = 0x00
WINDOWS_MINOR_VERSION_1 = 0x01
WINDOWS_MINOR_VERSION_2 = 0x02
WINDOWS_MINOR_VERSION_3 = 0x03
class NTLMRevision(object):
"""
@see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
"""
NTLMSSP_REVISION_W2K3 = 0x0F
class Negotiate(object):
"""
@see: https://msdn.microsoft.com/en-us/library/cc236650.aspx
"""
NTLMSSP_NEGOTIATE_56 = 0x80000000
NTLMSSP_NEGOTIATE_KEY_EXCH = 0x40000000
NTLMSSP_NEGOTIATE_128 = 0x20000000
NTLMSSP_NEGOTIATE_VERSION = 0x02000000
NTLMSSP_NEGOTIATE_TARGET_INFO = 0x00800000
NTLMSSP_REQUEST_NON_NT_SESSION_KEY = 0x00400000
NTLMSSP_NEGOTIATE_IDENTIFY = 0x00100000
NTLMSSP_NEGOTIATE_EXTENDED_SESSIONSECURITY = 0x00080000
NTLMSSP_TARGET_TYPE_SERVER = 0x00020000
NTLMSSP_TARGET_TYPE_DOMAIN = 0x00010000
NTLMSSP_NEGOTIATE_ALWAYS_SIGN = 0x00008000
NTLMSSP_NEGOTIATE_OEM_WORKSTATION_SUPPLIED = 0x00002000
NTLMSSP_NEGOTIATE_OEM_DOMAIN_SUPPLIED = 0x00001000
NTLMSSP_NEGOTIATE_NTLM = 0x00000200
NTLMSSP_NEGOTIATE_LM_KEY = 0x00000080
NTLMSSP_NEGOTIATE_DATAGRAM = 0x00000040
NTLMSSP_NEGOTIATE_SEAL = 0x00000020
NTLMSSP_NEGOTIATE_SIGN = 0x00000010
NTLMSSP_REQUEST_TARGET = 0x00000004
NTLM_NEGOTIATE_OEM = 0x00000002
NTLMSSP_NEGOTIATE_UNICODE = 0x00000001
class AvId(object):
"""
@see: https://msdn.microsoft.com/en-us/library/cc236646.aspx
"""
MsvAvEOL = 0x0000
MsvAvNbComputerName = 0x0001
MsvAvNbDomainName = 0x0002
MsvAvDnsComputerName = 0x0003
MsvAvDnsDomainName = 0x0004
MsvAvDnsTreeName = 0x0005
MsvAvFlags = 0x0006
MsvAvTimestamp = 0x0007
MsvAvSingleHost = 0x0008
MsvAvTargetName = 0x0009
MsvChannelBindings = 0x000A
def getPayLoadField(message, length, bufferOffset):
if length == 0:
return None
offset = sizeof(message) - sizeof(message.Payload)
start = bufferOffset - offset
end = start + length
return message.Payload.value[start:end]
class Version(CompositeType):
"""
@summary: Version structure as describe in NTLM spec
@see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
"""
def __init__(self, conditional):
CompositeType.__init__(self, conditional = conditional)
self.ProductMajorVersion = UInt8(MajorVersion.WINDOWS_MAJOR_VERSION_6)
self.ProductMinorVersion = UInt8(MinorVersion.WINDOWS_MINOR_VERSION_0)
self.ProductBuild = UInt16Le(6002)
self.Reserved = UInt24Le()
self.NTLMRevisionCurrent = UInt8(NTLMRevision.NTLMSSP_REVISION_W2K3)
class AvPair(CompositeType):
"""
@see: https://msdn.microsoft.com/en-us/library/cc236646.aspx
"""
def __init__(self):
CompositeType.__init__(self)
self.AvId = UInt16Le()
self.AvLen = UInt16Le(lambda:sizeof(self.Value))
self.Value = String(readLen = self.AvLen)
class MessageSignatureEx(CompositeType):
"""
@summary: Signature for message
@see: https://msdn.microsoft.com/en-us/library/cc422952.aspx
"""
def __init__(self):
CompositeType.__init__(self)
self.Version = UInt32Le(0x00000001, constant = True)
self.Checksum = String(readLen = CallableValue(8))
self.SeqNum = UInt32Le()
class NegotiateMessage(CompositeType):
"""
@summary: Message send from client to server to negotiate capability of NTLM Authentication
@see: https://msdn.microsoft.com/en-us/library/cc236641.aspx
"""
def __init__(self):
CompositeType.__init__(self)
self.Signature = String("NTLMSSP\x00", readLen = CallableValue(8), constant = True)
self.MessageType = UInt32Le(0x00000001, constant = True)
self.NegotiateFlags = UInt32Le()
self.DomainNameLen = UInt16Le()
self.DomainNameMaxLen = UInt16Le(lambda:self.DomainNameLen.value)
self.DomainNameBufferOffset = UInt32Le()
self.WorkstationLen = UInt16Le()
self.WorkstationMaxLen = UInt16Le(lambda:self.WorkstationLen.value)
self.WorkstationBufferOffset = UInt32Le()
self.Version = Version(conditional = lambda:(self.NegotiateFlags.value & Negotiate.NTLMSSP_NEGOTIATE_VERSION))
self.Payload = String()
class ChallengeMessage(CompositeType):
"""
@summary: Message send from server to client contains server challenge
@see: https://msdn.microsoft.com/en-us/library/cc236642.aspx
"""
def __init__(self):
CompositeType.__init__(self)
self.Signature = String("NTLMSSP\x00", readLen = CallableValue(8), constant = True)
self.MessageType = UInt32Le(0x00000002, constant = True)
self.TargetNameLen = UInt16Le()
self.TargetNameMaxLen = UInt16Le(lambda:self.TargetNameLen.value)
self.TargetNameBufferOffset = UInt32Le()
self.NegotiateFlags = UInt32Le()
self.ServerChallenge = String(readLen = CallableValue(8))
self.Reserved = String("\x00" * 8, readLen = CallableValue(8))
self.TargetInfoLen = UInt16Le()
self.TargetInfoMaxLen = UInt16Le(lambda:self.TargetInfoLen.value)
self.TargetInfoBufferOffset = UInt32Le()
self.Version = Version(conditional = lambda:(self.NegotiateFlags.value & Negotiate.NTLMSSP_NEGOTIATE_VERSION))
self.Payload = String()
def getTargetName(self):
return getPayLoadField(self, self.TargetNameLen.value, self.TargetNameBufferOffset.value)
def getTargetInfo(self):
return getPayLoadField(self, self.TargetInfoLen.value, self.TargetInfoBufferOffset.value)
def getTargetInfoAsAvPairArray(self):
"""
@summary: Parse Target info field to retrieve array of AvPair
@return: {map(AvId, str)}
"""
result = {}
s = Stream(self.getTargetInfo())
while(True):
avPair = AvPair()
s.readType(avPair)
if avPair.AvId.value == AvId.MsvAvEOL:
return result
result[avPair.AvId.value] = avPair.Value.value
class AuthenticateMessage(CompositeType):
"""
@summary: Last message in ntlm authentication
@see: https://msdn.microsoft.com/en-us/library/cc236643.aspx
"""
def __init__(self):
CompositeType.__init__(self)
self.Signature = String("NTLMSSP\x00", readLen = CallableValue(8), constant = True)
self.MessageType = UInt32Le(0x00000003, constant = True)
self.LmChallengeResponseLen = UInt16Le()
self.LmChallengeResponseMaxLen = UInt16Le(lambda:self.LmChallengeResponseLen.value)
self.LmChallengeResponseBufferOffset = UInt32Le()
self.NtChallengeResponseLen = UInt16Le()
self.NtChallengeResponseMaxLen = UInt16Le(lambda:self.NtChallengeResponseLen.value)
self.NtChallengeResponseBufferOffset = UInt32Le()
self.DomainNameLen = UInt16Le()
self.DomainNameMaxLen = UInt16Le(lambda:self.DomainNameLen.value)
self.DomainNameBufferOffset = UInt32Le()
self.UserNameLen = UInt16Le()
self.UserNameMaxLen = UInt16Le(lambda:self.UserNameLen.value)
self.UserNameBufferOffset = UInt32Le()
self.WorkstationLen = UInt16Le()
self.WorkstationMaxLen = UInt16Le(lambda:self.WorkstationLen.value)
self.WorkstationBufferOffset = UInt32Le()
self.EncryptedRandomSessionLen = UInt16Le()
self.EncryptedRandomSessionMaxLen = UInt16Le(lambda:self.EncryptedRandomSessionLen.value)
self.EncryptedRandomSessionBufferOffset = UInt32Le()
self.NegotiateFlags = UInt32Le()
self.Version = Version(conditional = lambda:(self.NegotiateFlags.value & Negotiate.NTLMSSP_NEGOTIATE_VERSION))
self.MIC = String("\x00" * 16, readLen = CallableValue(16))
self.Payload = String()
def getUserName(self):
return getPayLoadField(self, self.UserNameLen.value, self.UserNameBufferOffset.value)
def getDomainName(self):
return getPayLoadField(self, self.DomainNameLen.value, self.DomainNameBufferOffset.value)
def getLmChallengeResponse(self):
return getPayLoadField(self, self.LmChallengeResponseLen.value, self.LmChallengeResponseBufferOffset.value)
def getNtChallengeResponse(self):
return getPayLoadField(self, self.NtChallengeResponseLen.value, self.NtChallengeResponseBufferOffset.value)
def getEncryptedRandomSession(self):
return getPayLoadField(self, self.EncryptedRandomSessionLen.value, self.EncryptedRandomSessionBufferOffset.value)
def createAuthenticationMessage(NegFlag, domain, user, NtChallengeResponse, LmChallengeResponse, EncryptedRandomSessionKey, Workstation):
"""
@summary: Create an Authenticate Message
@param domain: {str} domain microsoft
@param user: {str} user microsoft
@param NtChallengeResponse: {str} Challenge response
@param LmChallengeResponse: {str} domain microsoft
@param EncryptedRandomSessionKey: {str} EncryptedRandomSessionKey
"""
message = AuthenticateMessage()
message.NegotiateFlags.value = NegFlag
#fill message
offset = sizeof(message)
message.DomainNameLen.value = len(domain)
message.DomainNameBufferOffset.value = offset
message.Payload.value += domain
offset += len(domain)
message.UserNameLen.value = len(user)
message.UserNameBufferOffset.value = offset
message.Payload.value += user
offset += len(user)
message.WorkstationLen.value = len(Workstation)
message.WorkstationBufferOffset.value = offset
message.Payload.value += Workstation
offset += len(Workstation)
message.LmChallengeResponseLen.value = len(LmChallengeResponse)
message.LmChallengeResponseBufferOffset.value = offset
message.Payload.value += LmChallengeResponse
offset += len(LmChallengeResponse)
message.NtChallengeResponseLen.value = len(NtChallengeResponse)
message.NtChallengeResponseBufferOffset.value = offset
message.Payload.value += NtChallengeResponse
offset += len(NtChallengeResponse)
message.EncryptedRandomSessionLen.value = len(EncryptedRandomSessionKey)
message.EncryptedRandomSessionBufferOffset.value = offset
message.Payload.value += EncryptedRandomSessionKey
offset += len(EncryptedRandomSessionKey)
return message
def expandDesKey(key):
"""
@summary: Expand the key from a 7-byte password key into a 8-byte DES key
"""
s = chr(((ord(key[0]) >> 1) & 0x7f) << 1)
s = s + chr(((ord(key[0]) & 0x01) << 6 | ((ord(key[1]) >> 2) & 0x3f)) << 1)
s = s + chr(((ord(key[1]) & 0x03) << 5 | ((ord(key[2]) >> 3) & 0x1f)) << 1)
s = s + chr(((ord(key[2]) & 0x07) << 4 | ((ord(key[3]) >> 4) & 0x0f)) << 1)
s = s + chr(((ord(key[3]) & 0x0f) << 3 | ((ord(key[4]) >> 5) & 0x07)) << 1)
s = s + chr(((ord(key[4]) & 0x1f) << 2 | ((ord(key[5]) >> 6) & 0x03)) << 1)
s = s + chr(((ord(key[5]) & 0x3f) << 1 | ((ord(key[6]) >> 7) & 0x01)) << 1)
s = s + chr((ord(key[6]) & 0x7f) << 1)
return s
def CurrentFileTimes():
"""
@summary: Current File times in 64 bits
@return : {str[8]}
"""
return struct.pack("Q", filetimes.dt_to_filetime(datetime.datetime.now()))
def DES(key, data):
"""
@summary: DES use in microsoft specification
@param key: {str} Des key on 56 bits or 7 bytes
@param data: {str} data to encrypt
"""
return pyDes.des(expandDesKey(key)).encrypt(data)
def DESL(key, data):
"""
@summary: an krosoft security function (triple des = des + des + des ;-))
@param key: {str} Des key
@param data: {str} encrypted data
"""
return DES(key[0:7], data) + DES(key[7:14], data) + DES(key[14:16] + "\x00" * 5, data)
def UNICODE(s):
"""
@param s: source
@return: {str} encoded in unicode
"""
return s.encode('utf-16le')
def MD4(s):
"""
@summary: compute the md4 sum
@param s: {str} input data
@return: {str} MD4(s)
"""
return hashlib.new('md4', s).digest()
def MD5(s):
"""
@summary: compute the md5 sum
@param s: {str} input data
@return: {str} MD5(s)
"""
return hashlib.new('md5', s).digest()
def Z(m):
"""
@summary: fill m zero in string
@param m: {int} size of string
@return: \x00 * m
"""
return "\x00" * m
def RC4K(key, plaintext):
"""
@summary: Context free of rc4 encoding
@param key: {str} key
@param plaintext: {str} plaintext
@return {str} encrypted text
"""
return rc4.crypt(rc4.RC4Key(key), plaintext)
def KXKEYv2(SessionBaseKey, LmChallengeResponse, ServerChallenge):
"""
@summary: Key eXchange Key for NTLMv2
@param SessionBaseKey: {str} computed by NTLMv1Anthentication or NTLMv2Authenticate function
@param LmChallengeResponse : {str} computed by NTLMv1Anthentication or NTLMv2Authenticate function
@param ServerChallenge : {str} Server chanllenge come from ChallengeMessage
@see: https://msdn.microsoft.com/en-us/library/cc236710.aspx
"""
return SessionBaseKey
def SEALKEY(ExportedSessionKey, client):
if client:
return MD5(ExportedSessionKey + "session key to client-to-server sealing key magic constant\0")
else:
return MD5(ExportedSessionKey + "session key to server-to-client sealing key magic constant\0")
def SIGNKEY(ExportedSessionKey, client):
if client:
return MD5(ExportedSessionKey + "session key to client-to-server signing key magic constant\0")
else:
return MD5(ExportedSessionKey + "session key to server-to-client signing key magic constant\0")
def HMAC_MD5(key, data):
"""
@summary: classic HMAC algorithm with MD5 sum
@param key: {str} key
@param data: {str} data
"""
return hmac.new(key, data, hashlib.md5).digest()
def NTOWFv2(Passwd, User, UserDom):
"""
@summary: Version 2 of NTLM hash function
@param Passwd: {str} Password
@param User: {str} Username
@param UserDom: {str} microsoft domain
@see: https://msdn.microsoft.com/en-us/library/cc236700.aspx
"""
return HMAC_MD5(MD4(UNICODE(Passwd)), UNICODE(User.upper() + UserDom))
def LMOWFv2(Passwd, User, UserDom):
"""
@summary: Same as NTOWFv2
@param Passwd: {str} Password
@param User: {str} Username
@param UserDom: {str} microsoft domain
@see: https://msdn.microsoft.com/en-us/library/cc236700.aspx
"""
return NTOWFv2(Passwd, User, UserDom)
def ComputeResponsev2(ResponseKeyNT, ResponseKeyLM, ServerChallenge, ClientChallenge, Time, ServerName):
"""
@summary: process NTLMv2 Authenticate hash
@param NegFlg: {int} Negotiation flags come from challenge message
@see: https://msdn.microsoft.com/en-us/library/cc236700.aspx
"""
Responserversion = "\x01"
HiResponserversion = "\x01"
temp = Responserversion + HiResponserversion + Z(6) + Time + ClientChallenge + Z(4) + ServerName
NTProofStr = HMAC_MD5(ResponseKeyNT, ServerChallenge + temp)
NtChallengeResponse = NTProofStr + temp
LmChallengeResponse = HMAC_MD5(ResponseKeyLM, ServerChallenge + ClientChallenge) + ClientChallenge
SessionBaseKey = HMAC_MD5(ResponseKeyNT, NTProofStr)
return NtChallengeResponse, LmChallengeResponse, SessionBaseKey
def MAC(handle, SigningKey, SeqNum, Message):
"""
@summary: generate signature for application message
@param handle: {rc4.RC4Key} handle on crypt
@param SigningKey: {str} Signing key
@param SeqNum: {int} Sequence number
@param Message: Message to sign
@see: https://msdn.microsoft.com/en-us/library/cc422952.aspx
"""
signature = MessageSignatureEx()
signature.SeqNum.value = SeqNum
#write the SeqNum
s = Stream()
s.writeType(signature.SeqNum)
signature.Checksum.value = rc4.crypt(handle, HMAC_MD5(SigningKey, s.getvalue() + Message)[:8])
return signature
def MIC(ExportedSessionKey, negotiateMessage, challengeMessage, authenticateMessage):
"""
@summary: Compute MIC signature
@param negotiateMessage: {NegotiateMessage}
@param challengeMessage: {ChallengeMessage}
@param authenticateMessage: {AuthenticateMessage}
@return: {str} signature
@see: https://msdn.microsoft.com/en-us/library/cc236676.aspx
"""
s = Stream()
s.writeType((negotiateMessage, challengeMessage, authenticateMessage))
return HMAC_MD5(ExportedSessionKey, s.getvalue())
class NTLMv2(sspi.IAuthenticationProtocol):
"""
@summary: Handle NTLMv2 Authentication
"""
def __init__(self, domain, user, password):
self._domain = domain
self._user = user
self._password = password
self._enableUnicode = False
#https://msdn.microsoft.com/en-us/library/cc236700.aspx
self._ResponseKeyNT = NTOWFv2(password, user, domain)
self._ResponseKeyLM = LMOWFv2(password, user, domain)
#For MIC computation
self._negotiateMessage = None
self._challengeMessage = None
self._authenticateMessage = None
def getNegotiateMessage(self):
"""
@summary: generate first handshake messgae
"""
self._negotiateMessage = NegotiateMessage()
self._negotiateMessage.NegotiateFlags.value = (Negotiate.NTLMSSP_NEGOTIATE_KEY_EXCH |
Negotiate.NTLMSSP_NEGOTIATE_128 |
Negotiate.NTLMSSP_NEGOTIATE_EXTENDED_SESSIONSECURITY |
Negotiate.NTLMSSP_NEGOTIATE_ALWAYS_SIGN |
Negotiate.NTLMSSP_NEGOTIATE_NTLM |
Negotiate.NTLMSSP_NEGOTIATE_SEAL |
Negotiate.NTLMSSP_NEGOTIATE_SIGN |
Negotiate.NTLMSSP_REQUEST_TARGET |
Negotiate.NTLMSSP_NEGOTIATE_UNICODE)
return self._negotiateMessage
def getAuthenticateMessage(self, s):
"""
@summary: Client last handshake message
@param s: {Stream} challenge message stream
@return: {(AuthenticateMessage, NTLMv2SecurityInterface)} Last handshake message and security interface use to encrypt
@see: https://msdn.microsoft.com/en-us/library/cc236676.aspx
"""
self._challengeMessage = ChallengeMessage()
s.readType(self._challengeMessage)
ServerChallenge = self._challengeMessage.ServerChallenge.value
ClientChallenge = random(64)
computeMIC = False
ServerName = self._challengeMessage.getTargetInfo()
infos = self._challengeMessage.getTargetInfoAsAvPairArray()
if infos.has_key(AvId.MsvAvTimestamp):
Timestamp = infos[AvId.MsvAvTimestamp]
computeMIC = True
else:
Timestamp = CurrentFileTimes()
NtChallengeResponse, LmChallengeResponse, SessionBaseKey = ComputeResponsev2(self._ResponseKeyNT, self._ResponseKeyLM, ServerChallenge, ClientChallenge, Timestamp, ServerName)
KeyExchangeKey = KXKEYv2(SessionBaseKey, LmChallengeResponse, ServerChallenge)
ExportedSessionKey = random(128)
EncryptedRandomSessionKey = RC4K(KeyExchangeKey, ExportedSessionKey)
domain, user = self._domain, self._user
if self._challengeMessage.NegotiateFlags.value & Negotiate.NTLMSSP_NEGOTIATE_UNICODE:
self._enableUnicode = True
domain, user = UNICODE(domain), UNICODE(user)
self._authenticateMessage = createAuthenticationMessage(self._challengeMessage.NegotiateFlags.value, domain, user, NtChallengeResponse, LmChallengeResponse, EncryptedRandomSessionKey, "")
if computeMIC:
self._authenticateMessage.MIC.value = MIC(ExportedSessionKey, self._negotiateMessage, self._challengeMessage, self._authenticateMessage)
else:
self._authenticateMessage.MIC._conditional = lambda:False
ClientSigningKey = SIGNKEY(ExportedSessionKey, True)
ServerSigningKey = SIGNKEY(ExportedSessionKey, False)
ClientSealingKey = SEALKEY(ExportedSessionKey, True)
ServerSealingKey = SEALKEY(ExportedSessionKey, False)
interface = NTLMv2SecurityInterface(rc4.RC4Key(ClientSealingKey), rc4.RC4Key(ServerSealingKey), ClientSigningKey, ServerSigningKey)
return self._authenticateMessage, interface
def getEncodedCredentials(self):
"""
@summary: return encoded credentials accorded with authentication protocol nego
@return: (domain, username, password)
"""
if self._enableUnicode:
return UNICODE(self._domain), UNICODE(self._user), UNICODE(self._password)
else:
return self._domain, self._user, self._password
class NTLMv2SecurityInterface(sspi.IGenericSecurityService):
"""
@summary: Generic Security Service for NTLM session
"""
def __init__(self, encryptHandle, decryptHandle, signingKey, verifyKey):
"""
@param encryptHandle: {rc4.RC4Key} rc4 keystream for encrypt phase
@param decryptHandle: {rc4.RC4Key} rc4 keystream for decrypt phase
@param signingKey: {str} signingKey
@param verifyKey: {str} verifyKey
"""
self._encryptHandle = encryptHandle
self._decryptHandle = decryptHandle
self._signingKey = signingKey
self._verifyKey = verifyKey
self._seqNum = 0
def GSS_WrapEx(self, data):
"""
@summary: Encrypt function for NTLMv2 security service
@param data: data to encrypt
@return: {str} encrypted data
"""
encryptedData = rc4.crypt(self._encryptHandle, data)
signature = MAC(self._encryptHandle, self._signingKey, self._seqNum, data)
self._seqNum += 1
s = Stream()
s.writeType(signature)
return s.getvalue() + encryptedData
def GSS_UnWrapEx(self, data):
"""
@summary: decrypt data with key exchange in Authentication protocol
@param data: {str}
"""
signature = MessageSignatureEx()
message = String()
s = Stream(data)
s.readType((signature, message))
#decrypt message
plaintextMessage = rc4.crypt(self._decryptHandle, message.value)
checksum = rc4.crypt(self._decryptHandle, signature.Checksum.value)
#recompute checksum
t = Stream()
t.writeType(signature.SeqNum)
verify = HMAC_MD5(self._verifyKey, t.getvalue() + plaintextMessage)[:8]
if verify != checksum:
raise error.InvalidExpectedDataException("NTLMv2SecurityInterface : Invalid checksum")
return plaintextMessage