def recv(self):
finished = False
forceRecv = 0
retAnswer = ''
while not finished:
# At least give me the MSRPCRespHeader, especially important for TCP/UDP Transports
self.response_data = self._transport.recv(
forceRecv, count=MSRPCRespHeader._SIZE)
self.response_header = MSRPCRespHeader(self.response_data)
# Ok, there might be situation, especially with large packets, that the transport layer didn't send us the full packet's contents
# So we gotta check we received it all
while (len(self.response_data) < self.response_header['frag_len']):
self.response_data += self._transport.recv(
forceRecv,
count=(self.response_header['frag_len'] -
len(self.response_data)))
off = self.response_header.get_header_size()
if self.response_header[
'type'] == MSRPC_FAULT and self.response_header[
'frag_len'] >= off + 4:
status_code = unpack("<L", self.response_data[off:off + 4])[0]
if rpc_status_codes.has_key(status_code):
raise Exception(rpc_status_codes[status_code])
else:
raise Exception('Unknown DCE RPC fault status code: %.8x' %
status_code)
if self.response_header['flags'] & MSRPC_LASTFRAG:
# No need to reassembly DCERPC
finished = True
else:
# Forcing Read Recv, we need more packets!
forceRecv = 1
answer = self.response_data[off:]
auth_len = self.response_header['auth_len']
if auth_len:
auth_len += 8
auth_data = answer[-auth_len:]
ntlmssp = ntlm.DCERPC_NTLMAuthHeader(data=auth_data)
answer = answer[:-auth_len]
if ntlmssp['auth_level'] == ntlm.NTLM_AUTH_PKT_PRIVACY:
if self.__flags & ntlm.NTLMSSP_NTLM2_KEY:
# TODO: FIX THIS, it's not calculating the signature well
# Since I'm not testing it we don't care... yet
answer, signature = ntlm.SEAL(
self.__flags,
self.__serverSigningKey,
self.__serverSealingKey,
answer,
answer,
self.__sequence,
self.__serverSealingHandle,
isDCE=True)
else:
answer, signature = ntlm.SEAL(
self.__flags,
self.__serverSigningKey,
self.__serverSealingKey,
answer,
answer,
self.__sequence,
self.__serverSealingHandle,
isDCE=True)
self.__sequence += 1
else:
ntlmssp = ntlm.DCERPC_NTLMAuthVerifier(data=auth_data)
if self.__flags & ntlm.NTLMSSP_NTLM2_KEY:
signature = ntlm.SIGN(self.__flags,
self.__serverSigningKey,
answer,
self.__sequence,
self.__serverSealingHandle,
isDCE=True)
else:
signature = ntlm.SIGN(self.__flags,
self.__serverSigningKey,
ntlmssp['data'],
self.__sequence,
self.__serverSealingHandle,
isDCE=True)
# Yes.. NTLM2 doesn't increment sequence when receiving
# the packet :P
self.__sequence += 1
if ntlmssp['auth_pad_len']:
answer = answer[:-ntlmssp['auth_pad_len']]
retAnswer += answer
return retAnswer
def _transport_send(self, rpc_packet, forceWriteAndx=0, forceRecv=0):
rpc_packet['ctx_id'] = self._ctx
if self.__auth_level in [
ntlm.NTLM_AUTH_PKT_INTEGRITY, ntlm.NTLM_AUTH_PKT_PRIVACY
]:
# Dummy verifier, just for the calculations
verifier = ntlm.DCERPC_NTLMAuthVerifier()
verifier['auth_pad_len'] = 0
pad = (8 - (len(rpc_packet.get_packet()) % 8)) % 8
if pad != 0:
rpc_packet['pduData'] = rpc_packet['pduData'] + '\x00' * pad
verifier['auth_pad_len'] = pad
verifier['auth_level'] = self.__auth_level
verifier['auth_ctx_id'] = self._ctx + 79231
verifier['data'] = ' ' * 12
rpc_packet['auth_data'] = str(verifier)
plain_data = rpc_packet['pduData']
if self.__auth_level == ntlm.NTLM_AUTH_PKT_PRIVACY:
if self.__flags & ntlm.NTLMSSP_NTLM2_KEY:
# When NTLM2 is on, we sign the whole pdu, but encrypt just
# the data, not the dcerpc header. Weird..
sealedMessage, signature = ntlm.SEAL(
self.__flags,
self.__clientSigningKey,
self.__clientSealingKey,
rpc_packet.get_packet()[:-16],
plain_data,
self.__sequence,
self.__clientSealingHandle,
isDCE=True)
else:
sealedMessage, signature = ntlm.SEAL(
self.__flags,
self.__clientSigningKey,
self.__clientSealingKey,
plain_data,
plain_data,
self.__sequence,
self.__clientSealingHandle,
isDCE=True)
rpc_packet['pduData'] = sealedMessage
else:
if self.__flags & ntlm.NTLMSSP_NTLM2_KEY:
# Interesting thing.. with NTLM2, what is is signed is the
# whole PDU, not just the data
signature = ntlm.SIGN(self.__flags,
self.__clientSigningKey,
rpc_packet.get_packet()[:-16],
self.__sequence,
self.__clientSealingHandle,
isDCE=True)
else:
signature = ntlm.SIGN(self.__flags,
self.__clientSigningKey,
plain_data,
self.__sequence,
self.__clientSealingHandle,
isDCE=True)
signature['auth_level'] = self.__auth_level
signature['auth_ctx_id'] = verifier['auth_ctx_id']
signature['auth_pad_len'] = pad
rpc_packet['auth_data'] = str(signature)
self.__sequence += 1
self._transport.send(rpc_packet.get_packet(),
forceWriteAndx=forceWriteAndx,
forceRecv=forceRecv)