Port scan with python

Introduction

I learned from a CTF book that port scanning can be done with python Start with the curiosity of "What? Can python do that?" In the process, I learned that multithreading is much faster than running single. Since it's a big deal, I'll leave both for comparison.

Be careful

Because it is NG to do port scan to an external site In the experiment, start up a virtual server using Virtualbox on your own PC I did a port scan on it. That's why "10.0.0.2" written in the source code of ↓↓ is the IP of your own virtual server.

1. 1. Simple port scan

Reference: https://qiita.com/najayama/items/728682bcae824c902046

The code I learned the most is this. There is no waste. Instead it's slow. On the contrary, because it was slow, I could feel the "effectiveness of multithreading".

simple-port-scanner.py

import socket

max_port = 6000
min_port = 1

target_host = input("Input target host name or address: ")

for port in range(min_port, max_port):
    #target_Attempt to connect to port number port of host
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    return_code = sock.connect_ex((target_host, port))
    sock.close()

    #socket.connect_ex returns 0 on success
    if return_code == 0:
        print("Port %d open!" % (port))

print("Complete!")

2. Multithreaded port scan

Reference: https://www.valuestar.work/news/archives/20

This is no less wasteful than it is. I use thread well so it's fast enough to die. 1. 1. Then it took about 1 second per port It took quite a while to do ports 1 to 1024, but with this program, the process was completed in about 3 seconds. thread is bad.

This time, I used it as a reference in the rush, so it is not a copy of the code, so it is not in a comparable form. I wish I could shape it so that I could compare it later ...

multi-port-scanner.py

import socket
import threading

scan_range = [1, 10000];

host = "10.0.0.2";

threads = [];
ports = [];
isopen = [];

def Run(port, i):
    con = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    return_code = con.connect_ex((host, port))
    con.close()

    if return_code == 0:
        isopen[i] = 1;
    
    
count = 0;
for port in range(scan_range[0], scan_range[1]):
    ports.append(port);
    isopen.append(0);
    thread = threading.Thread(target=Run, args=(port, count));
    thread.start();
    threads.append(thread);
    count = count + 1;

for i in range(len(threads)):
    threads[i].join();
    if isopen[i] == 1:
        print("%d open" % ports[i]);

in conclusion

I looked it up to study portscan The destructive power of thread left an impression on me more than I expected. Let's slowly look at the source code and organize it later

~ End ~