def negotiateSession(self, preferredDialect=None, negSessionResponse=None):
# We DON'T want to sign
self._Connection['ClientSecurityMode'] = 0
if self.RequireMessageSigning is True:
LOG.error('Signing is required, attack won\'t work!')
return
self._Connection['Capabilities'] = SMB2_GLOBAL_CAP_ENCRYPTION
currentDialect = SMB2_DIALECT_WILDCARD
# Do we have a negSessionPacket already?
if negSessionResponse is not None:
# Yes, let's store the dialect answered back
negResp = SMB2Negotiate_Response(negSessionResponse['Data'])
currentDialect = negResp['DialectRevision']
if currentDialect == SMB2_DIALECT_WILDCARD:
# Still don't know the chosen dialect, let's send our options
packet = self.SMB_PACKET()
packet['Command'] = SMB2_NEGOTIATE
negSession = SMB2Negotiate()
negSession['SecurityMode'] = self._Connection['ClientSecurityMode']
negSession['Capabilities'] = self._Connection['Capabilities']
negSession['ClientGuid'] = self.ClientGuid
if preferredDialect is not None:
negSession['Dialects'] = [preferredDialect]
else:
negSession['Dialects'] = [
SMB2_DIALECT_002, SMB2_DIALECT_21, SMB2_DIALECT_30
]
negSession['DialectCount'] = len(negSession['Dialects'])
packet['Data'] = negSession
packetID = self.sendSMB(packet)
ans = self.recvSMB(packetID)
if ans.isValidAnswer(STATUS_SUCCESS):
negResp = SMB2Negotiate_Response(ans['Data'])
self._Connection['MaxTransactSize'] = min(0x100000,
negResp['MaxTransactSize'])
self._Connection['MaxReadSize'] = min(0x100000, negResp['MaxReadSize'])
self._Connection['MaxWriteSize'] = min(0x100000,
negResp['MaxWriteSize'])
self._Connection['ServerGuid'] = negResp['ServerGuid']
self._Connection['GSSNegotiateToken'] = negResp['Buffer']
self._Connection['Dialect'] = negResp['DialectRevision']
if (negResp['SecurityMode'] & SMB2_NEGOTIATE_SIGNING_REQUIRED
) == SMB2_NEGOTIATE_SIGNING_REQUIRED:
LOG.error('Signing is required, attack won\'t work!')
return
if (negResp['Capabilities']
& SMB2_GLOBAL_CAP_LEASING) == SMB2_GLOBAL_CAP_LEASING:
self._Connection['SupportsFileLeasing'] = True
if (negResp['Capabilities']
& SMB2_GLOBAL_CAP_LARGE_MTU) == SMB2_GLOBAL_CAP_LARGE_MTU:
self._Connection['SupportsMultiCredit'] = True
if self._Connection['Dialect'] == SMB2_DIALECT_30:
# Switching to the right packet format
self.SMB_PACKET = SMB3Packet
if (negResp['Capabilities'] & SMB2_GLOBAL_CAP_DIRECTORY_LEASING
) == SMB2_GLOBAL_CAP_DIRECTORY_LEASING:
self._Connection['SupportsDirectoryLeasing'] = True
if (negResp['Capabilities'] & SMB2_GLOBAL_CAP_MULTI_CHANNEL
) == SMB2_GLOBAL_CAP_MULTI_CHANNEL:
self._Connection['SupportsMultiChannel'] = True
if (negResp['Capabilities'] & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES
) == SMB2_GLOBAL_CAP_PERSISTENT_HANDLES:
self._Connection['SupportsPersistentHandles'] = True
if (negResp['Capabilities'] &
SMB2_GLOBAL_CAP_ENCRYPTION) == SMB2_GLOBAL_CAP_ENCRYPTION:
self._Connection['SupportsEncryption'] = True
self._Connection['ServerCapabilities'] = negResp['Capabilities']
self._Connection['ServerSecurityMode'] = negResp['SecurityMode']
def negotiateSession(self, preferredDialect=None, negSessionResponse=None):
# Let's store some data for later use
self._Connection['ClientSecurityMode'] = SMB2_NEGOTIATE_SIGNING_ENABLED
if self.RequireMessageSigning is True:
self._Connection[
'ClientSecurityMode'] |= SMB2_NEGOTIATE_SIGNING_REQUIRED
self._Connection['Capabilities'] = SMB2_GLOBAL_CAP_ENCRYPTION
currentDialect = SMB2_DIALECT_WILDCARD
# Do we have a negSessionPacket already?
if negSessionResponse is not None:
# Yes, let's store the dialect answered back
negResp = SMB2Negotiate_Response(negSessionResponse['Data'])
currentDialect = negResp['DialectRevision']
if currentDialect == SMB2_DIALECT_WILDCARD:
# Still don't know the chosen dialect, let's send our options
packet = self.SMB_PACKET()
packet['Command'] = SMB2_NEGOTIATE
negSession = SMB2Negotiate()
negSession['SecurityMode'] = self._Connection['ClientSecurityMode']
negSession['Capabilities'] = self._Connection['Capabilities']
negSession['ClientGuid'] = self.ClientGuid
if preferredDialect is not None:
negSession['Dialects'] = [preferredDialect]
if preferredDialect == SMB2_DIALECT_311:
# Build the Contexts
contextData = SMB311ContextData()
contextData['NegotiateContextOffset'] = 64 + 38 + 2
contextData['NegotiateContextCount'] = 0
# Add an SMB2_NEGOTIATE_CONTEXT with ContextType as SMB2_PREAUTH_INTEGRITY_CAPABILITIES
# to the negotiate request as specified in section 2.2.3.1:
negotiateContext = SMB2NegotiateContext()
negotiateContext[
'ContextType'] = SMB2_PREAUTH_INTEGRITY_CAPABILITIES
preAuthIntegrityCapabilities = SMB2PreAuthIntegrityCapabilities(
)
preAuthIntegrityCapabilities['HashAlgorithmCount'] = 1
preAuthIntegrityCapabilities['SaltLength'] = 32
preAuthIntegrityCapabilities[
'HashAlgorithms'] = b'\x01\x00'
preAuthIntegrityCapabilities['Salt'] = ''.join([
rand.choice(string.ascii_letters) for _ in range(
preAuthIntegrityCapabilities['SaltLength'])
])
negotiateContext[
'Data'] = preAuthIntegrityCapabilities.getData()
negotiateContext['DataLength'] = len(
negotiateContext['Data'])
contextData['NegotiateContextCount'] += 1
pad = b'\xFF' * (8 - (negotiateContext['DataLength'] % 8))
negotiateContext2 = SMB2NegotiateContext()
negotiateContext2[
'ContextType'] = SMB2_COMPRESSION_CAPABILITIES
compressionCapabilities = SMB2CompressionCapabilities()
compressionCapabilities['CompressionAlgorithmCount'] = 1
compressionCapabilities['Padding'] = 0
compressionCapabilities['Flags'] = 0
compressionCapabilities[
'CompressionAlgorithms'] = b'\x01\x00'
negotiateContext2[
'Data'] = compressionCapabilities.getData()
negotiateContext2['DataLength'] = len(
negotiateContext2['Data'])
contextData['NegotiateContextCount'] += 1
negSession['ClientStartTime'] = contextData.getData()
negSession['Padding'] = b'\xFF\xFF'
# Subsequent negotiate contexts MUST appear at the first 8-byte aligned offset following the
# previous negotiate context.
negSession[
'NegotiateContextList'] = negotiateContext.getData(
) + pad + negotiateContext2.getData()
else:
negSession['Dialects'] = [
SMB2_DIALECT_002, SMB2_DIALECT_21, SMB2_DIALECT_30
]
negSession['DialectCount'] = len(negSession['Dialects'])
packet['Data'] = negSession
packetID = self.sendSMB(packet)
ans = self.recvSMB(packetID)
if ans.isValidAnswer(STATUS_SUCCESS):
negResp = SMB2Negotiate_Response(ans['Data'])
self._Connection['MaxTransactSize'] = min(0x100000,
negResp['MaxTransactSize'])
self._Connection['MaxReadSize'] = min(0x100000, negResp['MaxReadSize'])
self._Connection['MaxWriteSize'] = min(0x100000,
negResp['MaxWriteSize'])
self._Connection['ServerGuid'] = negResp['ServerGuid']
self._Connection['GSSNegotiateToken'] = negResp['Buffer']
self._Connection['Dialect'] = negResp['DialectRevision']
if (negResp['SecurityMode'] & SMB2_NEGOTIATE_SIGNING_REQUIRED) == SMB2_NEGOTIATE_SIGNING_REQUIRED or \
self._Connection['Dialect'] == SMB2_DIALECT_311:
self._Connection['RequireSigning'] = True
if self._Connection['Dialect'] == SMB2_DIALECT_311:
# Always Sign
self._Connection['RequireSigning'] = True
if (negResp['Capabilities']
& SMB2_GLOBAL_CAP_LEASING) == SMB2_GLOBAL_CAP_LEASING:
self._Connection['SupportsFileLeasing'] = True
if (negResp['Capabilities']
& SMB2_GLOBAL_CAP_LARGE_MTU) == SMB2_GLOBAL_CAP_LARGE_MTU:
self._Connection['SupportsMultiCredit'] = True
if self._Connection['Dialect'] >= SMB2_DIALECT_30:
# Switching to the right packet format
self.SMB_PACKET = SMB3Packet
if (negResp['Capabilities'] & SMB2_GLOBAL_CAP_DIRECTORY_LEASING
) == SMB2_GLOBAL_CAP_DIRECTORY_LEASING:
self._Connection['SupportsDirectoryLeasing'] = True
if (negResp['Capabilities'] & SMB2_GLOBAL_CAP_MULTI_CHANNEL
) == SMB2_GLOBAL_CAP_MULTI_CHANNEL:
self._Connection['SupportsMultiChannel'] = True
if (negResp['Capabilities'] & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES
) == SMB2_GLOBAL_CAP_PERSISTENT_HANDLES:
self._Connection['SupportsPersistentHandles'] = True
if (negResp['Capabilities'] &
SMB2_GLOBAL_CAP_ENCRYPTION) == SMB2_GLOBAL_CAP_ENCRYPTION:
self._Connection['SupportsEncryption'] = True
self._Connection['ServerCapabilities'] = negResp['Capabilities']
self._Connection['ServerSecurityMode'] = negResp['SecurityMode']
