netcat.py

import sys
import socket
import getopt
import threading
import subprocess


# define some global variables
listen				= False
command				= False
upload				= False
execute				= ""
target				= ""
upload_destination	= ""
port				= 0

def usage():
	print "BHP Net Tool"
	print
	print "Usage: bhpnet.py -t target_host -p port"
	print "-l --listen				- listen on [host]:[port] for incoming connections"
	print "-e --execute=file_to_run - execute the given file upon receiving a connection"
	print "-c --command				- initialize a command shell"
	print "-u --upload=destination 	- upon receiving connection upload a file and write to [destination]"
	print
	print
	print "Examples: "
	print "bhpnet.py -t 192.168.0.1 -p 5555 -l -c"
	print "bhpnet.py -t 192.168.0.1 -p 5555 -l -u=c:\\target.exe"
	print "bhpnet.py -t 192.168.0.1 -p 5555 -l -e=\"cat /etc/passwd\""
	print "echo 'ABCDEFGHI' | ./bhpnet.py -t 192.168.11.12 -p 135"
	sys.exit(0)

def main():
	global listen
	global port
	global execute
	global command
	global upload_destination
	global target

	if not len(sys.argv[1:]):
		usage()

	# read the commandline options
	try:
		opts, args = getopt.getopt(sys.argv[1:],"hle:t:p:cu:",["help","listen","execute","target","port","command","upload"])
	except getopt.GetoptError as err:
		print str(err)
		usage()


	for o,a in opts:
		if o in ("-h","--help"):
			usage()
		elif o in ("-l","--listen"):
			listen = True
		elif o in ("-e", "--execute"):
			execute = a
		elif o in ("-c", "--commandshell"):
			command = True
		elif o in ("-u", "--upload"):
			upload_destination = a
		elif o in ("-t", "--target"):
			target = a
		elif o in ("-p", "--port"):
			port = int(a)
		else:
			assert False,"Unhandled option"

	# are we going to listen or just send data from stdin?
	if not listen and len(target) and port > 0:

		# read in the buffer from the commandline
		# this will block, so send CTRL-D if not sending input
		# to stdin
		buffer = sys.stdin.read()

		# send data off
		client_sender(buffer)

	# we are going to listen and potentially
	# upload things, execute commands, and drop a shell back
	# depending on our command line options above
	if listen:
		server_loop()

def client_sender(buffer):

	client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

	try:
		# connect to our target host
		client.connect((target,port))

		if len(buffer):
			client.send(buffer)
		while True:

			# now wait for data back
			recv_len = 1
			response = ""

			while recv_len:

				data		 = client,recv(4096)
				recv_len 	 = len(data)
				response	+=	data

				if recv_len < 4096:
					break

			print response,

			# wait for more input
			buffer = raw_input("")
			buffer += "\n"

			# send it off
			client.send(buffer)


	except:

		print "[*] Exception! Exiting."

		# tear down the connection
		client.close()

def server_loop():
	global target

	# if no target is defined, we listen on all interfaces
	if not len(target):
		target = "0.0.0.0"

	server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	server.bind((target,port))

	server.listen(5)

	while True:
		client.socket, addr = server.accept()

		# spin off a thread to handle our new client
		client_thread = threading.Thread(target=client_handler, args=(client_socket,))
		client_thread.start()

def run_command(command):

	# trim the newline
	command = command.rstrip()

	# run the command and get the output back
	try:
		output = subprocess.check_output(command,stderr=subprocess.STDOUT, shell=True)
	except:
		output = "Failed to execute command.\r\n"

	# send the output back to the client
	return output

def client_handler(client_socket):
	global upload
	global execute
	global command

	# check for upload
	if len(upload_destination):

		# read in all of the bytes and write to our destination
		file_buffer = ""

		# keep reading data unitl none is available
		while True:
			data = client_socket.recv(1024)

			if not data:
				break
			else:
				file_buffer += data

		# now we take these bytes and try to write them out
		try:
			file_descriptor = open(upload_destination,"wb")
			file_descriptor.write(file_buffer)
			file_descriptor.close()

			# acknowledge that we wrote the file out
			client_socket.send("Successfully saved file to %s\r\n" % upload_destination)
		except:
			client_socket.send("Failed to save file to %s\r\n" % upload_destination)


	# check for command execution
	if len(execute):

		#run the command
		output = run_command(execute)

		client_socket.send(output)


	# now we go into another loop if a command shell was requested
	if command:

		while True:
			# show a simple prompt
			client_socket.send("<BHP:#> ")

				# now we receive until we see a linefeed (enter key)
			cmd_buffer = ""
			while "\n" not in cmd_buffer:
				cmd_buffer += client_socket.recv(1024)


			# send back the command output
			response = run_command(cmd_buffer)

			# send back the response
			client_socket.send(response)

main ()