IP spoofing

#!/usr/bin/env python
#coding:utf-8

'''IP-Spoofing is the forgery of IP addresses. The source address is notthe IP of the real network device the packet was sent over, but manuallyinserted one. Attackers use this technique either to hide the source ofthe attack or to circumvent a packet-filter or other security layers liketcp wrapper that block or accept connections depending on their source ipaddress.'''
IP-Spoofing is the forgery of IP addresses. The source address is not
the IP of the real network device the packet was sent over, but manually
inserted one. Attackers use this technique either to hide the source of
the attack or to circumvent a packet-filter or other security layers like
tcp wrapper that block or accept connections depending on their source ip
address.
'''
import sys
from scapy.all import send, IP, ICMP

if len(sys.argv) < 3:
    print sys.argv[0] + " <src_ip> <dst_ip>"
    sys.exit(1)

packet = IP(src=sys.argv[1], dst=sys.argv[2]) / ICMP()
answer = send(packet)

if answer:
    answer.show()

'''Source Code Note:    We create an IP packet that is included into an ICMP packet by definingIP() / ICMP(). This somewaht unusual but handy declaration syntax is madepossible by Scapy by overriding the / operator with the help of the __div__method.    The IP packet gets the source and destination IP as a parameter. The resulting packet object is dumped on the screen by calling the show() method on it(show2() would only display layer 2). Afterwards we send it by calling send()(here too we could use sendp() for layer2). Last but not least if we get anyresponse packets it is being printed on the screen. Of course we can onlyreceive a reply if it is sent to our network card. Therefore it could be necessaryto implement a Mitm attack if our host is not connected to the same hub as the targetsystem. In our case we do not have to care about a Mitm attack,because Scapy insertsour MAC address as source address and the destination MAC of the destination IPautomatically. Thus we can be sure the reply packet is directly sent back to us.    You can protect against IP spoofing by signing and encrypting all IP packets.A common case would be the protocols AH or ESP of the IPSec protocol family.'''
Source Code Note:
    We create an IP packet that is included into an ICMP packet by defining
IP() / ICMP(). This somewaht unusual but handy declaration syntax is made
possible by Scapy by overriding the / operator with the help of the __div__
method.
    The IP packet gets the source and destination IP as a parameter. The resulting pa
cket object is dumped on the screen by calling the show() method on it
(show2() would only display layer 2). Afterwards we send it by calling send()
(here too we could use sendp() for layer2). Last but not least if we get any
response packets it is being printed on the screen. Of course we can only
receive a reply if it is sent to our network card. Therefore it could be necessary
to implement a Mitm attack if our host is not connected to the same hub as the target
system. In our case we do not have to care about a Mitm attack,because Scapy inserts
our MAC address as source address and the destination MAC of the destination IP
automatically. Thus we can be sure the reply packet is directly sent back to us.
    You can protect against IP spoofing by signing and encrypting all IP packets.
A common case would be the protocols AH or ESP of the IPSec protocol family.

'''