Scapy Port Scanner - Set verbose mode in command line

Question

I have the following script scanning a host's ports.

Verbose mode is set initially to off verbose=0.

I want the user to be able to add '-verbose' in the command line to enable verbosity.

How should this be done?

import logging
logging.getLogger("scapy.runtime").setLevel(logging.ERROR)
import sys
from scapy.all import *

# Define end host and TCP port range
hostInput    = input("Enter a remote host to scan: ")
host  = socket.gethostbyname(hostInput)
port_range = [21,22,23,25,53,80,110,135,137,138,139,443,1433,1434,8080]

# Send SYN with random Src Port for each Dst port
for dst_port in port_range:
    src_port = random.randint(1025,65534)
    resp = sr1(
        IP(dst=host)/TCP(sport=src_port,dport=dst_port,flags="S"),timeout=1,
        verbose=0,
    )

    if resp is None:
        print(f"{host}:{dst_port} is filtered (silently dropped).")

    elif(resp.haslayer(TCP)):
        if(resp.getlayer(TCP).flags == 0x12):
            # Send a gratuitous RST to close the connection
            send_rst = sr(
                IP(dst=host)/TCP(sport=src_port,dport=dst_port,flags='R'),
                timeout=1,
                verbose=1,
            )
            print(f"{host}:{dst_port} is open.")

        elif (resp.getlayer(TCP).flags == 0x14):
            print(f"{host}:{dst_port} is closed.")

    elif(resp.haslayer(ICMP)):
        if(
            int(resp.getlayer(ICMP).type) == 3 and
            int(resp.getlayer(ICMP).code) in [1,2,3,9,10,13]
        ):
            print(f"{host}:{dst_port} is filtered (silently dropped).")

Did you try anything at all? Like `verbose = '-verbose' in sys.argv`? — Tim Roberts, Jun 27 '21 at 05:10
I'm not sure where or how I should do that in the script. Also, where and when should the user enter this? As it is, the user is prompted for a host address, so would the verbose option be entered then? Do you have an example? — IlludiumPu36, Jun 27 '21 at 05:17

darth baba · Accepted Answer · 2021-06-27T06:20:09.227

1

Argparse module makes it easy to write user-friendly command-line interfaces. The program defines what arguments it requires, and argparse will figure out how to parse those out of sys.argv. The argparse module also automatically generates help and usage messages and issues errors when users give the program invalid arguments.

Example on running it in terminal/cmd:

python3 logger.py --remote_host 127.0.0.1 --verbose 0

import logging
logging.getLogger("scapy.runtime").setLevel(logging.ERROR)
import sys
from scapy.all import *
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("--remote_host")
parser.add_argument("--verbose")
args = parser.parse_args()

# Define end host and TCP port range
hostInput    = args.remote_host
host  = socket.gethostbyname(hostInput)
port_range = [21,22,23,25,53,80,110,135,137,138,139,443,1433,1434,8080]

# Send SYN with random Src Port for each Dst port
for dst_port in port_range:
    src_port = random.randint(1025,65534)
    resp = sr1(
        IP(dst=host)/TCP(sport=src_port,dport=dst_port,flags="S"),timeout=1,
        verbose=int(args.verbose),
    )

    if resp is None:
        print(f"{host}:{dst_port} is filtered (silently dropped).")

    elif(resp.haslayer(TCP)):
        if(resp.getlayer(TCP).flags == 0x12):
            # Send a gratuitous RST to close the connection
            send_rst = sr(
                IP(dst=host)/TCP(sport=src_port,dport=dst_port,flags='R'),
                timeout=1,
                verbose=int(args.verbose),
            )
            print(f"{host}:{dst_port} is open.")

        elif (resp.getlayer(TCP).flags == 0x14):
            print(f"{host}:{dst_port} is closed.")

    elif(resp.haslayer(ICMP)):
        if(
            int(resp.getlayer(ICMP).type) == 3 and
            int(resp.getlayer(ICMP).code) in [1,2,3,9,10,13]
        ):
            print(f"{host}:{dst_port} is filtered (silently dropped).")

edited Jun 27 '21 at 06:20

answered Jun 27 '21 at 05:38

darth baba

1,277
5
13

Thanks. Running python3 ScapyScanner.py --remote_host 127.0.0.1 --verbose 0 I get SyntaxError: invalid syntax – IlludiumPu36 Jun 27 '21 at 05:49
TypeError: gethostbyname() argument 1 must be str, bytes or bytearray, not None This is line 44... – IlludiumPu36 Jun 27 '21 at 05:53
Line 43 -- hostInput = args.remote_host Line 44 -- host = socket.gethostbyname(hostInput) – IlludiumPu36 Jun 27 '21 at 05:57
what python version are you using? – darth baba Jun 27 '21 at 05:59
socket.gethostbyname translates hostname to IPv4, so instead of 127.0.0.1 you can pass in any valid dns address example: www.slashdot.org and also convert args.verbose to int. – darth baba Jun 27 '21 at 06:04
1

In Idle I am going to run in Python shell and running: python3 logger.py --remote_host google.com --verbose 0 I get invalid syntax – IlludiumPu36 Jun 27 '21 at 06:07
Have you run this? – IlludiumPu36 Jun 27 '21 at 06:08
I just installed through pip3 install argparse. Installed. Still getting syntax error. Anything else I need to do? – IlludiumPu36 Jun 27 '21 at 06:12
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/234243/discussion-between-illudiumpu36-and-darth-baba). – IlludiumPu36 Jun 27 '21 at 06:15
Nope, I think it should work, it is working on my end you can try converting args.remote_host to str i.e, str(args.hostInput) before passing it to socket.gethostbyname – darth baba Jun 27 '21 at 06:15

Scapy Port Scanner - Set verbose mode in command line

1 Answers1