IDS.py

from scapy.all import *
from random import randint

payload = 'GET /proxy.org HTTP/1.1\r\nUser-Agent: curl/7.35.0\r\nHost: mit.edu\r\n\r\n'

ip = '23.66.32.128'

sport = randint(30000, 50000)

if __name__ == '__main__':
    print 'Using port ', sport
    syn = IP(dst=ip) / TCP(sport=sport, dport=80, flags='S')
    syn_ack = sr1(syn)
    ack = send(IP(dst=ip) / TCP(sport=sport, dport=80, flags='A', seq=syn_ack[TCP].ack, ack=syn_ack[TCP].seq + 1))
    rst = IP(dst=ip, ttl=40) / TCP(sport=sport, dport=80, flags='R', seq=2333, ack=21)
    send(rst)
    reply = sr(IP(dst=ip) / TCP(sport=sport, dport=80, flags='PA', seq=syn_ack[TCP].ack, ack=syn_ack[TCP].seq + 1) / payload)
    pkts = sniff(filter="tcp and host 59.66.135.76 and port {}".format(sport), count=5, prn=lambda x : x.sprintf('{IP:%IP.src% -> %IP.dst%\n}{Raw:%Raw.load%\n}'))
    content = pkts[-1]
    send(IP(dst=ip) / TCP(sport=sport, dport=80, flags='A', seq=content[TCP].ack, ack=content[TCP].seq + len(content) - 54))