added basic tools

README.md

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+# Simple TCP proxy written in Python
+
+### To find a local host to listen
+```bash
+ifconfig 
+```
+post should be 192.168.*.*
+
+sudo ./proxy.py 127.0.0.1 21 ftp.target.ca 21 True 

proxy.py

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+import sys
+import socket
+import threading
+
+
+# this is a pretty hex dumping function directly taken from
+# http://code.activestate.com/recipes/142812-hex-dumper/
+
+def hexdump(src, length=16):
+    result = []
+    digits = 4 if isinstance(src, str) else 2
+
+    for i in range(0, len(src), length):
+        s = src[i:i + length]
+        hexa = b' '.join([b"%0*X" % (digits, ord(x)) for x in s])
+        text = b''.join([x if 0x20 <= ord(x) < 0x7F else b'.' for x in s])
+        result.append(
+            b"%04X   %-*s   %s" % (i, length * (digits + 1), hexa, text))
+
+    print(b'\n'.join(result))
+
+
+def receive_from(connection):
+    buffer = b''
+
+    # We set a 2 second time-out. Depending on your target this may need
+    # to be adjusted
+    connection.settimeout(2)
+
+    try:
+
+        # keep reading into the buffer until there's no more data or we
+        # time-out
+        while True:
+            data = connection.recv(4096)
+            if not data:
+                break
+            buffer += data
+
+    except TimeoutError:
+        pass
+
+    return buffer
+
+
+# modify any requests destined for the remote host
+def request_handler(buffer):
+    # perform packet modifications
+    return buffer
+
+
+# modify any responses destined for the local host
+def response_handler(buffer):
+    # perform packet modifications
+    return buffer
+
+
+def proxy_handler(client_socket, remote_host, remote_port, receive_first):
+    # connect to the remote host
+    remote_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    remote_socket.connect((remote_host, remote_port))
+
+    # receive data from the remote end if necessary
+    if receive_first:
+        remote_buffer = receive_from(remote_socket)
+        hexdump(remote_buffer)
+
+        # send it to our response handler
+        remote_buffer = response_handler(remote_buffer)
+
+        # if we have data to send to our local client send it
+        if len(remote_buffer):
+            print("[<==] Sending %d bytes to localhost." % len(remote_buffer))
+            client_socket.send(remote_buffer)
+
+    # now let's loop and read from local, send to remote, send to local
+    # rinse wash repeat
+    while True:
+        # read from local host
+        local_buffer = receive_from(client_socket)
+
+        if len(local_buffer):
+            print("[==>] Received %d bytes from localhost." % len(local_buffer))
+            hexdump(local_buffer)
+
+            # send it to our request handler
+            local_buffer = request_handler(local_buffer)
+
+            # send off the data to the remote host
+            remote_socket.send(local_buffer)
+            print("[==>] Sent to remote.")
+
+        # receive back the response
+        remote_buffer = receive_from(remote_socket)
+
+        if len(remote_buffer):
+            print("[<==] Received %d bytes from remote." % len(remote_buffer))
+            hexdump(remote_buffer)
+
+            # send to our response handler
+            remote_buffer = response_handler(remote_buffer)
+
+            # send the response to the local socket
+            client_socket.send(remote_buffer)
+
+            print("[<==] Sent to localhost.")
+
+        # if no more data on either side close the connections
+        if not len(local_buffer) or not len(remote_buffer):
+            client_socket.close()
+            remote_socket.close()
+            print("[*] No more data. Closing connections.")
+            break
+
+
+def server_loop(local_host, local_port, remote_host, remote_port,
+                receive_first):
+    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+
+    try:
+        server.bind((local_host, local_port))
+    except socket.error as exc:
+        print("[!!] Failed to listen on %s:%d" % (local_host,
+                                                  local_port))
+        print("[!!] Check for other listening sockets or correct "
+              "permissions.")
+        print(f"[!!] Caught exception error: {exc}")
+        sys.exit(0)
+
+    print("[*] Listening on %s:%d" % (local_host, local_port))
+
+    server.listen(5)
+
+    while True:
+        client_socket, addr = server.accept()
+
+        # print out the local connection information
+        print("[==>] Received incoming connection from %s:%d" % (
+            addr[0], addr[1]))
+
+        # start a thread to talk to the remote host
+        proxy_thread = threading.Thread(target=proxy_handler, args=(
+            client_socket, remote_host, remote_port, receive_first))
+        proxy_thread.start()
+
+
+def main():
+    # no fancy command line parsing here
+    if len(sys.argv[1:]) != 5:
+        print("Usage: ./proxy.py [localhost] [localport] [remotehost] "
+              "[remoteport] [receive_first]")
+        print("Example: ./proxy.py 127.0.0.1 9000 10.12.132.1 9000 True")
+        sys.exit(0)
+
+    # setup local listening parameters
+    local_host = sys.argv[1]
+    local_port = int(sys.argv[2])
+
+    # setup remote target
+    remote_host = sys.argv[3]
+    remote_port = int(sys.argv[4])
+
+    # this tells our proxy to connect and receive data
+    # before sending to the remote host
+    receive_first = sys.argv[5]
+
+    if "True" in receive_first:
+        receive_first = True
+    else:
+        receive_first = False
+
+    # now spin up our listening socket
+    server_loop(local_host, local_port, remote_host, remote_port, receive_first)
+
+
+main()

scanner.py

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+import socket
+import os
+import struct
+import threading
+from ipaddress import ip_address, ip_network
+from ctypes import *
+
+# host to listen on
+host = "192.168.43.66"
+
+# subnet to target
+tgt_subnet = "192.168.43.0/24"
+
+# magic we'll check ICMP responses for
+tgt_message = "PYTHONRULES!"
+
+
+def udp_sender(sub_net, magic_message):
+    sender = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+
+    for ip in ip_network(sub_net).hosts():
+        sender.sendto(magic_message.encode('utf-8'), (str(ip), 65212))
+
+
+class IP(Structure):
+    _fields_ = [
+        ("ihl", c_ubyte, 4),
+        ("version", c_ubyte, 4),
+        ("tos", c_ubyte),
+        ("len", c_ushort),
+        ("id", c_ushort),
+        ("offset", c_ushort),
+        ("ttl", c_ubyte),
+        ("protocol_num", c_ubyte),
+        ("sum", c_ushort),
+        ("src", c_uint32),
+        ("dst", c_uint32)
+    ]
+
+    def __new__(cls, socket_buffer=None):
+        return cls.from_buffer_copy(socket_buffer)
+
+    def __init__(self, socket_buffer=None):
+        self.socket_buffer = socket_buffer
+
+        # map protocol constants to their names
+        self.protocol_map = {1: "ICMP", 6: "TCP", 17: "UDP"}
+
+        # human readable IP addresses
+        self.src_address = socket.inet_ntoa(struct.pack("@I", self.src))
+        self.dst_address = socket.inet_ntoa(struct.pack("@I", self.dst))
+
+        # human readable protocol
+        try:
+            self.protocol = self.protocol_map[self.protocol_num]
+        except IndexError:
+            self.protocol = str(self.protocol_num)
+
+
+class ICMP(Structure):
+    _fields_ = [
+        ("type", c_ubyte),
+        ("code", c_ubyte),
+        ("checksum", c_ushort),
+        ("unused", c_ushort),
+        ("next_hop_mtu", c_ushort)
+    ]
+
+    def __new__(cls, socket_buffer):
+        return cls.from_buffer_copy(socket_buffer)
+
+    def __init__(self, socket_buffer):
+        self.socket_buffer = socket_buffer
+
+
+# create a raw socket and bind it to the public interface
+if os.name == "nt":
+    socket_protocol = socket.IPPROTO_IP
+else:
+    socket_protocol = socket.IPPROTO_ICMP
+
+sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol)
+
+sniffer.bind((host, 0))
+
+# we want the IP headers included in the capture
+sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
+
+# if we're on Windows we need to send some ioctl
+# to setup promiscuous mode
+if os.name == "nt":
+    sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)
+
+# start sending packets
+t = threading.Thread(target=udp_sender, args=(tgt_subnet, tgt_message))
+t.start()
+
+try:
+    while True:
+
+        # read in a single packet
+        raw_buffer = sniffer.recvfrom(65535)[0]
+
+        # create an IP header from the first 20 bytes of the buffer
+        ip_header = IP(raw_buffer[:20])
+
+        print("Protocol: %s %s -> %s" % (
+            ip_header.protocol,
+            ip_header.src_address,
+            ip_header.dst_address)
+              )
+
+        # if it's ICMP we want it
+        if ip_header.protocol == "ICMP":
+
+            # calculate where our ICMP packet starts
+            offset = ip_header.ihl * 4
+            buf = raw_buffer[offset:offset + sizeof(ICMP)]
+
+            # create our ICMP structure
+            icmp_header = ICMP(buf)
+
+            print("ICMP -> Type: %d Code: %d" % (
+                icmp_header.type,
+                icmp_header.code)
+                  )
+
+            # now check for the TYPE 3 and CODE 3 which indicates
+            # a host is up but no port available to talk to           
+            if icmp_header.code == 3 and icmp_header.type == 3:
+
+                # check to make sure we are receiving the response 
+                # that lands in our subnet
+                if ip_address(ip_header.src_address) in ip_network(tgt_subnet):
+
+                    # test for our magic message
+                    if raw_buffer[len(raw_buffer)
+                       - len(tgt_message):] == tgt_message:
+                        print("Host Up: %s" % ip_header.src_address)
+
+# handle CTRL-C
+except KeyboardInterrupt:
+    # if we're on Windows turn off promiscuous mode
+    if os.name == "nt":
+        sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)

sniffer_basic.py

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+import socket
+import os
+
+# host to listen on
+host = "192.168.43.66"
+
+# create a raw socket and bind it to the public interface
+if os.name == "nt":
+    socket_protocol = socket.IPPROTO_IP
+else:
+    socket_protocol = socket.IPPROTO_ICMP
+
+sniffer = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket_protocol) 
+
+sniffer.bind((host, 0))
+
+# we want the IP headers included in the capture
+sniffer.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
+
+# if we're on Windows we need to send an IOCTL
+# to setup promiscuous mode
+if os.name == "nt": 
+    sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)
+
+# read in a single packet
+print(sniffer.recvfrom(65535))
+
+# if we're on Windows turn off promiscuous mode
+if os.name == "nt":
+    sniffer.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)