Ajouter DHCP2.py

2024-10-18 12:53:31 +02:00
parent 4d07e898e6
commit 3696a98c0a
1 changed files with 121 additions and 0 deletions
@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+"""scapy-dhcp-listener.py
+Listen for DHCP packets using scapy to learn when LAN 
+hosts request IP addresses from DHCP Servers.
+Copyright (C) 2018 Jonathan Cutrer
+License Dual MIT, 0BSD
+"""
+
+from __future__ import print_function
+from scapy.all import *
+import time
+
+__version__ = "0.0.3"
+
+# Fixup function to extract dhcp_options by key
+def get_option(dhcp_options, key):
+
+    must_decode = ['hostname', 'domain', 'vendor_class_id']
+    try:
+        for i in dhcp_options:
+            if i[0] == key:
+                # If DHCP Server Returned multiple name servers 
+                # return all as comma seperated string.
+                if key == 'name_server' and len(i) > 2:
+                    return ",".join(i[1:])
+                # domain and hostname are binary strings,
+                # decode to unicode string before returning
+                elif key in must_decode:
+                    return i[1].decode()
+                else: 
+                    return i[1]        
+    except:
+        pass
+
+
+def handle_dhcp_packet(packet):
+
+    # Match DHCP discover
+    if DHCP in packet and packet[DHCP].options[0][1] == 1:
+        print('---')
+        print('New DHCP Discover')
+        #print(packet.summary())
+        #print(ls(packet))
+        hostname = get_option(packet[DHCP].options, 'hostname')
+        print(f"Host {hostname} ({packet[Ether].src}) asked for an IP")
+
+
+    # Match DHCP offer
+    elif DHCP in packet and packet[DHCP].options[0][1] == 2:
+        print('---')
+        print('New DHCP Offer')
+        #print(packet.summary())
+        #print(ls(packet))
+
+        subnet_mask = get_option(packet[DHCP].options, 'subnet_mask')
+        lease_time = get_option(packet[DHCP].options, 'lease_time')
+        router = get_option(packet[DHCP].options, 'router')
+        name_server = get_option(packet[DHCP].options, 'name_server')
+        domain = get_option(packet[DHCP].options, 'domain')
+
+        print(f"DHCP Server {packet[IP].src} ({packet[Ether].src}) "
+              f"offered {packet[BOOTP].yiaddr}")
+
+        print(f"DHCP Options: subnet_mask: {subnet_mask}, lease_time: "
+              f"{lease_time}, router: {router}, name_server: {name_server}, "
+              f"domain: {domain}")
+
+
+    # Match DHCP request
+    elif DHCP in packet and packet[DHCP].options[0][1] == 3:
+        print('---')
+        print('New DHCP Request')
+        #print(packet.summary())
+        #print(ls(packet))
+
+        requested_addr = get_option(packet[DHCP].options, 'requested_addr')
+        hostname = get_option(packet[DHCP].options, 'hostname')
+        print(f"Host {hostname} ({packet[Ether].src}) requested {requested_addr}")
+
+
+    # Match DHCP ack
+    elif DHCP in packet and packet[DHCP].options[0][1] == 5:
+        print('---')
+        print('New DHCP Ack')
+        #print(packet.summary())
+        #print(ls(packet))
+
+        subnet_mask = get_option(packet[DHCP].options, 'subnet_mask')
+        lease_time = get_option(packet[DHCP].options, 'lease_time')
+        router = get_option(packet[DHCP].options, 'router')
+        name_server = get_option(packet[DHCP].options, 'name_server')
+
+        print(f"DHCP Server {packet[IP].src} ({packet[Ether].src}) "
+              f"acked {packet[BOOTP].yiaddr}")
+
+        print(f"DHCP Options: subnet_mask: {subnet_mask}, lease_time: "
+              f"{lease_time}, router: {router}, name_server: {name_server}")
+
+    # Match DHCP inform
+    elif DHCP in packet and packet[DHCP].options[0][1] == 8:
+        print('---')
+        print('New DHCP Inform')
+        #print(packet.summary())
+        #print(ls(packet))
+
+        hostname = get_option(packet[DHCP].options, 'hostname')
+        vendor_class_id = get_option(packet[DHCP].options, 'vendor_class_id')
+
+        print(f"DHCP Inform from {packet[IP].src} ({packet[Ether].src}) "
+              f"hostname: {hostname}, vendor_class_id: {vendor_class_id}")
+
+    else:
+        print('---')
+        print('Some Other DHCP Packet')
+        print(packet.summary())
+        print(ls(packet))
+
+    return
+
+if __name__ == "__main__":
+    sniff(filter="udp and (port 67 or 68)", prn=handle_dhcp_packet)