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Diffstat (limited to 'mitmproxy/examples/dns_spoofing.py')
| -rw-r--r-- | mitmproxy/examples/dns_spoofing.py | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/mitmproxy/examples/dns_spoofing.py b/mitmproxy/examples/dns_spoofing.py new file mode 100644 index 00000000..7eb79695 --- /dev/null +++ b/mitmproxy/examples/dns_spoofing.py @@ -0,0 +1,50 @@ +""" +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
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