Active Scanning with Scapy

Scanning Networks with Scapy

Nmap implements several types of scans and can be used to detect the versions of operating systems and services; it can also perform custom vulnerability scanning. Here we’ll implement a couple of simple scans using scapy in Python.

SYN scan : A SYN scan sends a TCP SYN packet to a port and looks for a SYN/ACK packet in response.
DNS scan : A DNS scan tests whether a DNS server is running on the target system.

Scapy makes it easy to create and send custom packets over the network and to sniff network traffic for responses.

Port Scan

from scapy.all import *
import ipaddress

ports = [25,80,53,443,445,3306,8080,8443]

def SynScan(host):
    ans,unans = sr(IP(dst=host) /
                   TCP(sport=33333, dport=ports, flags="S")
                   ,timeout=2,verbose=0)
    print("Open ports at %s:" % host)
    for (s,r,) in ans:
        if s[TCP].dport == r[TCP].sport and r[TCP].flags == "SA":
            print(s[TCP].dport)

def DNSScan(host):
    ans,unans  = sr(IP(dst=host) /
                    UDP(dport=53) /
                    DNS(rd=1,qd=DNSQR(qname="google.com"))
                    ,timeout=2,verbose=0)
    if ans and ans[UDP]:
        print("DNS Server at %s" % host)

host = input("Enter IP Address: ")
try:
    ipaddress.ip_address(host)
except:
    print("Invalid address")
    exit(-1)

SynScan(host)
DNSScan(host)

SYN Scan

def SynScan(host):
    ans,unans = sr(IP(dst=host) /
                   TCP(sport=33333, dport=ports, flags="S")
                   ,timeout=2,verbose=0)
    print("Open ports at %s:" % host)
    for (s,r,) in ans:
        if s[TCP].dport == r[TCP].sport and r[TCP].flags == "SA":
            print(s[TCP].dport)

DNS Scan

def DNSScan(host):
    ans,unans  = sr(IP(dst=host) /
                    UDP(dport=53) /
                    DNS(rd=1,qd=DNSQR(qname="google.com"))
                    ,timeout=2,verbose=0)
    if ans and ans[UDP]:
        print("DNS Server at %s" % host)

Source

Python for Cybersecurity - Howard E Poston