50 lines
1.7 KiB
Python
50 lines
1.7 KiB
Python
"""
|
|
This inline scripts makes it possible to use mitmproxy in scenarios where IP spoofing has been used to redirect
|
|
connections to mitmproxy. The way this works is that we rely on either the TLS Server Name Indication (SNI) or the
|
|
Host header of the HTTP request.
|
|
Of course, this is not foolproof - if an HTTPS connection comes without SNI, we don't
|
|
know the actual target and cannot construct a certificate that looks valid.
|
|
Similarly, if there's no Host header or a spoofed Host header, we're out of luck as well.
|
|
Using transparent mode is the better option most of the time.
|
|
|
|
Usage:
|
|
mitmproxy
|
|
-p 443
|
|
-s dns_spoofing.py
|
|
# Used as the target location if neither SNI nor host header are present.
|
|
-R http://example.com/
|
|
mitmdump
|
|
-p 80
|
|
-R http://localhost:443/
|
|
|
|
(Setting up a single proxy instance and using iptables to redirect to it
|
|
works as well)
|
|
"""
|
|
import re
|
|
|
|
|
|
# This regex extracts splits the host header into host and port.
|
|
# Handles the edge case of IPv6 addresses containing colons.
|
|
# https://bugzilla.mozilla.org/show_bug.cgi?id=45891
|
|
parse_host_header = re.compile(r"^(?P<host>[^:]+|\[.+\])(?::(?P<port>\d+))?$")
|
|
|
|
|
|
def request(context, flow):
|
|
if flow.client_conn.ssl_established:
|
|
flow.request.scheme = "https"
|
|
sni = flow.client_conn.connection.get_servername()
|
|
port = 443
|
|
else:
|
|
flow.request.scheme = "http"
|
|
sni = None
|
|
port = 80
|
|
|
|
host_header = flow.request.pretty_host
|
|
m = parse_host_header.match(host_header)
|
|
if m:
|
|
host_header = m.group("host").strip("[]")
|
|
if m.group("port"):
|
|
port = int(m.group("port"))
|
|
|
|
flow.request.host = sni or host_header
|
|
flow.request.port = port |