HTTP/1.1 Request Smuggling Defense using Cryptographic Message Binding (new draft)

I've submitted a new -00 draft
for draft-nygren-httpbis-http11-request-binding:

   HTTP/1.1 Message Binding adds new hop-by-hop header fields that are
   cryptographically bound to requests and responses.  The keys used are
   negotiated out-of-band from the HTTP datastream (such as via TLS
   Exporters).  These header fields allow endpoints to detect and
   mitigate desynchronization attacks, such as HTTP Request Smuggling,
   that exist due to datastream handling differences.

While it would be great if the entire world could switch to HTTP/2 and
HTTP/3,
that just isn't feasible as there are legacy HTTP/1.1 clients that need to
be supported, as well as a large ecosystem of HTTP/1.1 Intermediaries and
Origin Servers.

This proposal provides a hop-by-hop defense mechanism that allows endpoints
to defend HTTP/1.1 traffic against Request Smuggling attacks without
fundamentally changing the HTTP/1.1 protocol, and in a way which can
hopefully drop-in to auto-negotiate and "just work" to provide
defenses.  There are still quite a few different directions we could take
the design, as discussed briefly in the draft, as well as some open issues
around how particular details get implemented.

Note that this is focused on H1.  While H2 and H3 have streamids and other
ways to convey information out-of-band, H1 lacks those.  You can see this
as a way of getting stream ID equivalents into H1 in a protected but
minimally invasive manner.

I'm looking forward to discussing this in Montreal in two weeks to see if
this is something that other implementers (especially of Intermediaries and
Origin Servers) would be  interested in.  I'd also be thrilled to add in
one or more co-authors as this adds the most value if it is implemented and
deployed by as many vendors and open source projects as possible.

Best, Erik



[try #3 at sending to the list, this time with a different email address]

---------- Forwarded message ---------
From: <internet-drafts@ietf.org>
Date: Thu, Oct 16, 2025 at 6:23 PM
Subject: New Version Notification for
draft-nygren-httpbis-http11-request-binding-00.txt
To: Erik Nygren <erik+ietf@nygren.org>, Mike Bishop <mbishop@evequefou.be>


A new version of Internet-Draft
draft-nygren-httpbis-http11-request-binding-00.txt has been successfully
submitted by Erik Nygren and posted to the
IETF repository.

Name:     draft-nygren-httpbis-http11-request-binding
Revision: 00
Title:    HTTP/1.1 Request Smuggling Defense using Cryptographic Message
Binding
Date:     2025-10-16
Group:    Individual Submission
Pages:    15
URL:
https://www.ietf.org/archive/id/draft-nygren-httpbis-http11-request-binding-00.txt
Status:
https://datatracker.ietf.org/doc/draft-nygren-httpbis-http11-request-binding/
HTML:
https://www.ietf.org/archive/id/draft-nygren-httpbis-http11-request-binding-00.html
HTMLized:
https://datatracker.ietf.org/doc/html/draft-nygren-httpbis-http11-request-binding


Abstract:

   HTTP/1.1 Message Binding adds new hop-by-hop header fields that are
   cryptographically bound to requests and responses.  The keys used are
   negotiated out-of-band from the HTTP datastream (such as via TLS
   Exporters).  These header fields allow endpoints to detect and
   mitigate desynchronization attacks, such as HTTP Request Smuggling,
   that exist due to datastream handling differences.



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