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Unknown Key-Share Attacks on Uses of TLS with the Session Description Protocol (SDP)
draft-ietf-mmusic-sdp-uks-07

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Date Rev. By Action
2021-01-14
07 (System) RFC Editor state changed to AUTH48-DONE from AUTH48
2020-05-22
07 (System) RFC Editor state changed to AUTH48 from RFC-EDITOR
2020-03-16
07 (System) RFC Editor state changed to RFC-EDITOR from REF
2019-09-24
07 (System) RFC Editor state changed to REF from EDIT
2019-08-26
07 Gunter Van de Velde Assignment of request for Last Call review by OPSDIR to Ron Bonica was marked no-response
2019-08-19
07 (System) IANA Action state changed to RFC-Ed-Ack from Waiting on RFC Editor
2019-08-19
07 (System) IANA Action state changed to Waiting on RFC Editor from Waiting on Authors
2019-08-16
07 (System) IANA Action state changed to Waiting on Authors from In Progress
2019-08-15
07 (System) IANA Action state changed to In Progress
2019-08-15
07 (System) RFC Editor state changed to EDIT from MISSREF
2019-08-14
07 (System) RFC Editor state changed to MISSREF
2019-08-14
07 (System) IESG state changed to RFC Ed Queue from Approved-announcement sent
2019-08-14
07 (System) Announcement was received by RFC Editor
2019-08-13
07 Cindy Morgan IESG state changed to Approved-announcement sent from Approved-announcement to be sent
2019-08-13
07 Cindy Morgan IESG has approved the document
2019-08-13
07 Cindy Morgan Closed "Approve" ballot
2019-08-13
07 Cindy Morgan Ballot approval text was generated
2019-08-13
07 Adam Roach IESG state changed to Approved-announcement to be sent from IESG Evaluation::AD Followup
2019-08-13
07 Adam Roach RFC Editor Note was changed
2019-08-13
07 Adam Roach RFC Editor Note for ballot was generated
2019-08-13
07 Adam Roach RFC Editor Note for ballot was generated
2019-08-12
07 Roman Danyliw [Ballot comment]
Thank you for addressing my DISCUSS and COMMENTs.
2019-08-12
07 Roman Danyliw [Ballot Position Update] Position for Roman Danyliw has been changed to No Objection from Discuss
2019-08-09
07 Benjamin Kaduk
[Ballot comment]
Thanks for these updates; they are a big improvement.

In Section 3.2

  The absence of an identity binding does not relax this …
[Ballot comment]
Thanks for these updates; they are a big improvement.

In Section 3.2

  The absence of an identity binding does not relax this requirement;
  if a peer provided no identity binding, a zero-length extension MUST
  be present to be considered valid.

For some reason my brain keeps trying to tell me that this could be
misinterpreted somehow, as implying that if the peer doesn't implement
this extension it would be considered invalid.  But I don't see any
actual specific problems with this text, so it's probably fine.

  An "external_id_hash" extension that is any length other than 0 or 32
  is invalid and MUST cause the receiving endpoint to generate a fatal
  "decode_error" alert.

Very pedantic here, but the numbers aren't quite right, as the
"external_id_hash" extension would be length 1 or 33 due to the length
octet.  We'd have to say that the "binding_hash" is length 0 or 32 to be
pedantically correct.

Section 6

  Without identity assertions, the mitigations in this document prevent
  the session splicing attack described in Section 4.  Defense against
  session concatenation (Section 5) additionally requires protocol
  peers are not able to claim the certificate fingerprints of other
  entities.

nit: "requires that".
2019-08-09
07 Benjamin Kaduk Ballot comment text updated for Benjamin Kaduk
2019-08-09
07 Benjamin Kaduk
[Ballot comment]
Thanks for these updates; they are a bit improvement.

In Section 3.2

  The absence of an identity binding does not relax this …
[Ballot comment]
Thanks for these updates; they are a bit improvement.

In Section 3.2

  The absence of an identity binding does not relax this requirement;
  if a peer provided no identity binding, a zero-length extension MUST
  be present to be considered valid.

For some reason my brain keeps trying to tell me that this could be
misinterpreted somehow, as implying that if the peer doesn't implement
this extension it would be considered invalid.  But I don't see any
actual specific problems with this text, so it's probably fine.

  An "external_id_hash" extension that is any length other than 0 or 32
  is invalid and MUST cause the receiving endpoint to generate a fatal
  "decode_error" alert.

Very pedantic here, but the numbers aren't quite right, as the
"external_id_hash" extension would be length 1 or 33 due to the length
octet.  We'd have to say that the "binding_hash" is length 0 or 32 to be
pedantically correct.

Section 6

  Without identity assertions, the mitigations in this document prevent
  the session splicing attack described in Section 4.  Defense against
  session concatenation (Section 5) additionally requires protocol
  peers are not able to claim the certificate fingerprints of other
  entities.

nit: "requires that".
2019-08-09
07 Benjamin Kaduk [Ballot Position Update] Position for Benjamin Kaduk has been changed to No Objection from Discuss
2019-08-09
07 (System) Sub state has been changed to AD Followup from Revised ID Needed
2019-08-09
07 (System) IANA Review state changed to Version Changed - Review Needed from IANA OK - Actions Needed
2019-08-09
07 Martin Thomson New version available: draft-ietf-mmusic-sdp-uks-07.txt
2019-08-09
07 (System) New version approved
2019-08-09
07 (System) Request for posting confirmation emailed to previous authors: Eric Rescorla , Martin Thomson
2019-08-09
07 Martin Thomson Uploaded new revision
2019-08-09
07 Martin Thomson Uploaded new revision
2019-08-08
06 Jean Mahoney Assignment of request for Last Call review by GENART to Jari Arkko was marked no-response
2019-08-08
06 Cindy Morgan IESG state changed to IESG Evaluation::Revised I-D Needed from IESG Evaluation
2019-08-07
06 Barry Leiba [Ballot Position Update] New position, No Objection, has been recorded for Barry Leiba
2019-08-07
06 Warren Kumari [Ballot Position Update] New position, No Objection, has been recorded for Warren Kumari
2019-08-07
06 Suresh Krishnan [Ballot Position Update] New position, No Objection, has been recorded for Suresh Krishnan
2019-08-06
06 Alvaro Retana [Ballot Position Update] New position, No Objection, has been recorded for Alvaro Retana
2019-08-06
06 Alissa Cooper
[Ballot comment]
Section 2.3: s/This attack/The unknown key share attack/

Section 3: s/Neither SIP nor WebRTC identity providers are not required/Neither SIP nor WebRTC identity …
[Ballot comment]
Section 2.3: s/This attack/The unknown key share attack/

Section 3: s/Neither SIP nor WebRTC identity providers are not required/Neither SIP nor WebRTC identity providers are required/
2019-08-06
06 Alissa Cooper [Ballot Position Update] New position, No Objection, has been recorded for Alissa Cooper
2019-08-05
06 Roman Danyliw
[Ballot discuss]
(1) Section 3.2.  There are a few places where further clarity on error handling would be helpful:

-- Per “A peer that receives …
[Ballot discuss]
(1) Section 3.2.  There are a few places where further clarity on error handling would be helpful:

-- Per “A peer that receives an "external_id_hash" extension that does not match the value of the identity binding from its peer MUST immediately fail the TLS handshake with an error”, which TLS error alert?

-- Per “A peer that receives an identity binding, but does not receive an ‘external_id_hash’extension MAY choose to fail the connection”, if it does “fail the connection”, with which error alert?
2019-08-05
06 Roman Danyliw
[Ballot comment]
(2) I support Ben’s DISCUSS on the clarity of Section 3.2. I would add a few additional observations:

** Per the sentence, “The …
[Ballot comment]
(2) I support Ben’s DISCUSS on the clarity of Section 3.2. I would add a few additional observations:

** Per the sentence, “The resulting string is then encoded using UTF-8”, shouldn’t this JSON text already be UTF-8 per Section 8.1 of RFC8259 -- what’s the new encoding to be done?

** Recommend a citation for the WebRTC identity assertion, SDP identity attribute and PASSPoRT formats earlier than the last sentence of the relevant paragraph

(3) Section 3.2.  The second “Note” in this section likely is meant to be generic guidance regardless of whether SDP or PASSPoRT is used.  However, since the first “Note” only applies to SDP, it could be read that this crypto agility guidance only applies to PASSPoRT.  Recommend using a different convention.

(4) Section 3.  Per “Neither SIP nor WebRTC identity providers are not required to perform this validation”, this sentence has a triple negative (i.e., neither, nor and not).  Please rephrase to clarify that these providers are required to validate.
2019-08-05
06 Roman Danyliw [Ballot Position Update] New position, Discuss, has been recorded for Roman Danyliw
2019-08-05
06 Benjamin Kaduk
[Ballot discuss]
There are both pretty minor points, in the grand scheme of things, but I
do think it would be hazardous to publish the …
[Ballot discuss]
There are both pretty minor points, in the grand scheme of things, but I
do think it would be hazardous to publish the document without
addressing them.

The semantics surrounding the "external_id_hash" TLS extension seem
insufficiently specified to admit interoperable implementation.  In
Section 3.2 we read that it "carries a hash of the identity assertion that
communicating peers have exchanged", as if there was a single
distinguished identity assertion for the session.  But, if we read on,
we learn that there is not one identity assertion, but (in the general
case) two, one for each party, and that what seems to actually be
intended is that each party sends the hash of the identity assertion
corresponding to the sender's identity, with the requirements to send an
empty external_id_hash if the party in question is not providing
identity bindings.  Additionally, the text about having an empty
"external_id_hash" extension in ClientHello or
ServerHello/EncryptedExtensions is written in a way that implies that
all parties generate a ClientHello and all parties generate a
ServerHello or EncryptedExtensions message, whereas these are actually
conditional on whether the party is acting as (D)TLS client or server.

Similarly, the current text for the last sentence of Section 3.2 ("In
TLS 1.3, the "external_id_hash" extension MUST be sent in the
EncryptedExtensions message.") can be (mis)read as implying that all
EncryptedExtensions messages sent by TLS servers that implement this
specification must include this extension, which would violate the TLS
extension-negotiation model since it mandates the server sending an
extension without regard to the client having indicated support for the
extension.  Perhaps "MUST NOT be sent in the TLS 1.3 ServerHello message"
conveys the restriction more clearly?
(A similar comment applies to the corresponding statement in Section
4.3, which interestingly enough already has a "In TLS 1.3, the
"external_session_id" extension MUST NOT be included in a ServerHello."
disclaimer in addition to the problematic sentence.)
2019-08-05
06 Benjamin Kaduk
[Ballot comment]
Section 2

  The attacker obtains an identity assertion for an identity it
  controls, but binds that to the fingerprint of one …
[Ballot comment]
Section 2

  The attacker obtains an identity assertion for an identity it
  controls, but binds that to the fingerprint of one peer.  The
  attacker is then able to cause a TLS connection to be established
  where two endpoints communicate.  The victim that has its fingerprint
  copied by the attack correctly believes that it is communicating with
  the other victim; however, the other victim incorrectly believes that
  it is communicating with the attacker.

nit: maybe this could be reworded for improved clarity.  Perhaps, "two
endponts other than the attacker communicate" or "two victim endpoints".

  A similar attack can be mounted without any communications
  established based on the SDP "fingerprint" attribute [FINGERPRINT].

At this point in the document, I don't know how to interpret "without
any communications established based on".

Section 2.1

  1.  An attacker can only modify the parts of the session signaling
      for a session that they are part of, which is limited to their
      own offers and answers.

nit(?): the first part of the sentence suggests that the attacker can
modify their peers' offers/answers, and it's not entirely clear (from a
rhetorical sense) how the latter clause is supposed to relate to the
first.

  The combination of these two constraints make the spectrum of
  possible attacks quite limited.  An attacker is only able to switch
  its own certificate fingerprint for a valid certificate that is
  acceptable to its peer.  Attacks therefore rely on joining two
  separate sessions into a single session.

nit: It's not clear to me (at this point in the document) whether this
is "victim A connects to attacker and also to victim B, and attacker
merges the first session into the second", or "victim A connects to
attacker and attacker connects to victim B, and attacker splices the two
together and steps out of the way".  (I assume the latter, but the text
hasn't clarified it yet.)

Section 2.3

  Third-party call control (3PCC) [RFC3725] is a technique where a
  signaling peer establishes a call that is terminated by a different
  entity.  This attack is very similar to the 3PCC technique, except
  where the TLS peers are aware of the use of 3PCC.

nit: Rhetorically-wise, I don't know what "except" is intended to mean
here.  Is the attack like 3PCC but in normal 3PCC the peers are unaware
of 3PCC use and in the attack they are?  The other way around?  ("except
that in the 3PCC case the TLS peers are aware of its use" would
disambiguate fine, I think.)

  It is understood that this technique will prevent the use of 3PCC if
  peers have different views of the involved identities, or the value
  of SDP "tls-id" attributes.

nit: understood by whom?  (I don't think that we need "It is understood
that" at all.)

Section 3

  The identity assertions used for WebRTC (Section 7 of [WEBRTC-SEC])
  and the SIP PASSPoRT using in SIP identity ([SIP-ID], [PASSPoRT]) are
  bound to the certificate fingerprint of an endpoint.  An attacker

nit: s/using/used/

  causes an identity binding to be created that binds an identity they
  control to the fingerprint of a first victim.

nit: I think we want "An attacker can cause" or "In an unknown-key-share
attack, an attacker causes".

  really talking to the first victim.  The attacker only needs to
  create an identity assertion that covers a certificate fingerprint of
  the first victim.

Well, and actually cause the traffic to shuffle around so the victims
are sending/receiving from each other.

  The problem might appear to be caused by the fact that the authority
  that certifies the identity binding is not required to verify that
  the entity requesting the binding controls the keys associated with
  the fingerprints.  Neither SIP nor WebRTC identity providers are not
  required to perform this validation.  However, validation of keys by
  the identity provided is not relevant because verifying control of
  the associated keys is not a necessary condition for a secure
  protocol, nor would it be sufficient to prevent attack [SIGMA].

nit: in the last sentence, I'm not sure that "validation of keys by the
identity provided" is correct; "identity provider" would make more
sense.

  This form of unknown key-share attack is possible without
  compromising signaling integrity, unless the defenses described in

nit: I'd suggest s/possible/even possible/

  Section 4 are used.  Endpoints MUST use the "external_session_id"
  extension (see Section 4.3) in addition to the "external_id_hash"
  (Section 3.2) so that two calls between the same parties can't be
  altered by an attacker.

nit(?): These normative requirements kind of come out of nowhere, in
terms of the flow of language.  Maybe "In order to prevent this attack,
endpoints MUST", or just move the normative requirements closer to the
mechanisms themselves?

Section 3.2

  A WebRTC identity assertion is provided as a JSON [JSON] object that
  is encoded into a JSON text.  The resulting string is then encoded
  using UTF-8 [UTF8].  The content of the "external_id_hash" extension

I don't really understand the separate UTF-8 step -- RFC 8259 already
requires text to be UTF-8 encoded.

I think this section would be easier to read if the different cases of
identity encoding/transmission were broken out into a bulleted or
enumerated list (the latter might make it easier to extend in the
future): right now I think we have (1) pure WebRTC, (2) SDP "identity",
and (3) SIP PASSPoRT, but I'm not 100% sure I'm reading the text
properly.

If that's done, it would also be a good opportunity to clarify that the
note about hash agility applies to the TLS extension as a whole, not
just the PASSPoRT case.

  Where a PASSPoRT is used, the compact form of the PASSPoRT MUST be
  expanded into the full form.  The base64 encoding used in the SIP

nit: this is written to assume that only compact PASSPoRTs will ever be
used, which IIUC is not the case.

                                                    This allows its peer
  to include a hash of its identity binding.  An endpoint without an
  identity binding MUST include an empty "external_id_hash" extension
  in its ServerHello or EncryptedExtensions message, to indicate
  support for the extension.

nit: and that it has validated the client's identity binding?

  A peer that receives an "external_id_hash" extension that does not
  match the value of the identity binding from its peer MUST
  immediately fail the TLS handshake with an error.  This includes
  cases where the binding is absent, in which case the extension MUST
  be present and empty.

nit: I'd suggest rewording the second sentence as follows (since the
conditional logic on "extension present but binding absent" could be
confusing:

% The absence of an identity binding does not relax this requirement --
% an extension received when the peer has not provided an identity
% binding on the signalling layer must still be validated to have the
% zero-length extension body.

  A peer that receives an identity binding, but does not receive an
  "external_id_hash" extension MAY choose to fail the connection,
  though it is expected that implementations written prior to the
  definition of the extensions in this document will not support both
  for some time.

nit: I don't think the comma after "binding" is needed.
Also, is the "not" intended?  I'm not entirely sure what "both" is
intended to refer to.

Section 4

nit(?): There's an annoying lack of parallelism in the Section titles
for Sections 3 and 4, though I don't have a good suggestion for Section
4's title -- "Attack on Raw Fingerprints" is the best I can do right
now.

  Even if the integrity session signaling can be relied upon, an

nit: s/integrity session signaling/session signaling integrity/?

Section 4.1

  another honest endpoint.  The attacker convinces the endpoint that
  their session has completed, and that the session with the other
  endpoint has succeeded.

Even with the benfit of the figure, I'm not sure I am properly
understanding the distinction between "completed" and "succeeded".  Is
the idea that the "completed" session finishes a DTLS handshake and then
immediately hangs up?  Or is this entirely at the signalling layer?

                For this reason, it might be necessary to permit the
  signaling from Patsy to reach Norma to allow Patsy to receive a call
  setup completion signal, such as a SIP ACK.  Once the second session
  is established, Mallory might cause DTLS packets sent by Norma to
  Patsy to be dropped.  It is likely that these DTLS packets will be
  discarded by Patsy as Patsy will already have a successful DTLS
  connection established.

nit: Is this "it is likely these packets would be discarded even if
Mallory lets them through"?

  This attack creates an asymmetry in the beliefs about the identity of
  peers.  However, this attack is only possible if the victim (Norma)
  is willing to conduct two sessions nearly simultaneously, if the
  attacker (Mallory) is on the network path between the victims, and if
  the same certificate - and therefore SDP "fingerprint" attribute
  value - is used in both sessions.

This is the same certificate used by Norma in both sessions, right?

Section 4.3

  Where RTP and RTCP [RTP] are not multiplexed, it is possible that the
  two separate DTLS connections carrying RTP and RTCP can be switched.
  This is considered benign since these protocols are designed to be
  distinguishable.  RTP/RTCP multiplexing is advised to address this
  problem.

What does "switched" mean?  That Mallory could swap the data contents
around as an active MITM?

  This defense is not effective if an attacker can rewrite "tls-id"
  values in signaling.  Only the mechanism in "external_id_hash" is
  able to defend against an attacker that can compromise session
  integrity.

Please help me check my understanding: in terms of just the operation of
the TLS extensions, "external_id_hash" and "external_session_id" provide
similar protection, in that they are just validating that what's in the
TLS handshake matches what's in the signalling layer.  The added
protection from "external_id_hash" only comes when the endpoints
actually go and contact the peers' IdP to validate the identity
assertions that are transmitted in the signalling layer.
If my understanding is correct, we should probably add a bit more text
here indicating the need for more validation than just the validation of
the TLS extension contents that this document describes.

Section 5

  In the absence of any higher-level concept of peer identity, the use
  of session identifiers does not prevent session concatenation if the
  attacker is able to copy the session identifier from one signaling
  session to another.  This kind of attack is prevented by systems that
  enable peer authentication such as WebRTC identity [WEBRTC-SEC] or
  SIP identity [SIP-ID].  However, session concatenation remains
  possible at higher layers: an attacker can establish two independent
  sessions and simply forward any data it receives from one into the
  other.

And in such a case the attacker has access to the media plaintext, too,
right?

  Use of the "external_session_id" does not guarantee that the identity
  of the peer at the TLS layer is the same as the identity of the
  signaling peer.  The advantage an attacker gains by concatenating
  sessions is limited unless it is assumed that signaling and TLS peers
  are the same.  If a secondary protocol uses the signaling channel
  with the assumption that the signaling and TLS peers are the same
  then that protocol is vulnerable to attack unless they also validate
  the identity of peers at both layers.

Is this paragraph describing a case like in
draft-ietf-rtcweb-security-arch, where we do send (and verify) identity
assertions at the signalling layer?  That is, the verification at the
IdP counts for validation at the "secondary protocol" layer and the
verification that the TLS extension matches the signalling constitutes
verification at the TLS layer, thereby achieving the validation "at both
layers"?

  It is important to note that multiple connections can be created
  within the same signaling session.  An attacker might concatenate
  only part of a session, choosing to terminate some connections (and
  optionally forward data) while arranging to have peers interact
  directly for other connections.  It is even possible to have
  different peers interact for each connection.  This means that the
  actual identity of the peer for one connection might differ from the
  peer on another connection.

How do or could the mitigations specified in this document address these
attacks?

Section 8.2

I don't see how [BASE64] is only informative; we require base64-decoding
for some of the procedures.
2019-08-05
06 Benjamin Kaduk [Ballot Position Update] New position, Discuss, has been recorded for Benjamin Kaduk
2019-08-05
06 Mirja Kühlewind [Ballot Position Update] New position, No Objection, has been recorded for Mirja Kühlewind
2019-08-05
06 Deborah Brungard [Ballot Position Update] New position, No Objection, has been recorded for Deborah Brungard
2019-08-04
06 Alexey Melnikov [Ballot Position Update] New position, No Objection, has been recorded for Alexey Melnikov
2019-08-01
06 (System) IANA Review state changed to IANA OK - Actions Needed from Version Changed - Review Needed
2019-07-18
06 Adam Roach IESG state changed to IESG Evaluation from Waiting for Writeup::AD Followup
2019-07-17
06 Cindy Morgan Placed on agenda for telechat - 2019-08-08
2019-07-17
06 Adam Roach Ballot has been issued
2019-07-17
06 Adam Roach [Ballot Position Update] New position, Yes, has been recorded for Adam Roach
2019-07-17
06 Adam Roach Created "Approve" ballot
2019-07-17
06 Adam Roach Ballot writeup was changed
2019-07-17
06 (System) Sub state has been changed to AD Followup from Revised ID Needed
2019-07-17
06 (System) IANA Review state changed to Version Changed - Review Needed from IANA - Not OK
2019-07-17
06 Cindy Morgan New version available: draft-ietf-mmusic-sdp-uks-06.txt
2019-07-17
06 (System) Secretariat manually posting. Approvals already received
2019-07-17
06 Cindy Morgan Uploaded new revision
2019-07-12
05 Adam Roach Needs a new version to address https://mailarchive.ietf.org/arch/msg/mmusic/fEa5P8rdGsR9-LIZIXFvBhTBdqs
2019-07-12
05 Adam Roach IESG state changed to Waiting for Writeup::Revised I-D Needed from Waiting for Writeup
2019-06-19
05 (System) IANA Review state changed to IANA - Not OK from IANA - Review Needed
2019-06-19
05 Sabrina Tanamal
(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has completed its review of draft-ietf-mmusic-sdp-uks-05. If any part of this review is inaccurate, please let …
(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has completed its review of draft-ietf-mmusic-sdp-uks-05. If any part of this review is inaccurate, please let us know.

IANA understands that, upon approval of this document, there is a single action which IANA must complete.

In the TLS ExtensionType Values registry at https://www.iana.org/assignments/tls-extensiontype-values/, we'll add the following entries:

TBD1 external_id_hash CH, EE [RFC-to-be]
TBD2 external_session_id Encrypted [RFC-to-be]

As this document requests registrations in a Specification Required (see RFC 8126) registry, the IESG-designated experts for the TLS ExtensionType Values have asked that you send a review request to the mailing list (see RFC 8447, Section 17). Expert review will need to be completed before your document can be approved for publication as an RFC.

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

Thank you,

Sabrina Tanamal
Senior IANA Services Specialist
2019-06-19
05 (System) IESG state changed to Waiting for Writeup from In Last Call
2019-06-08
05 Russ Housley Request for Last Call review by SECDIR Completed: Has Issues. Reviewer: Russ Housley. Sent review to list.
2019-06-07
05 Gunter Van de Velde Request for Last Call review by OPSDIR is assigned to Ron Bonica
2019-06-07
05 Gunter Van de Velde Request for Last Call review by OPSDIR is assigned to Ron Bonica
2019-06-06
05 Jean Mahoney Request for Last Call review by GENART is assigned to Jari Arkko
2019-06-06
05 Jean Mahoney Request for Last Call review by GENART is assigned to Jari Arkko
2019-06-06
05 Tero Kivinen Request for Last Call review by SECDIR is assigned to Russ Housley
2019-06-06
05 Tero Kivinen Request for Last Call review by SECDIR is assigned to Russ Housley
2019-06-05
05 Cindy Morgan IANA Review state changed to IANA - Review Needed
2019-06-05
05 Cindy Morgan
The following Last Call announcement was sent out (ends 2019-06-19):

From: The IESG
To: IETF-Announce
CC: mmusic-chairs@ietf.org, adam@nostrum.com, mmusic@ietf.org, draft-ietf-mmusic-sdp-uks@ietf.org, Bo …
The following Last Call announcement was sent out (ends 2019-06-19):

From: The IESG
To: IETF-Announce
CC: mmusic-chairs@ietf.org, adam@nostrum.com, mmusic@ietf.org, draft-ietf-mmusic-sdp-uks@ietf.org, Bo Burman , bo.burman@ericsson.com
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Unknown Key Share Attacks on uses of TLS with the Session Description Protocol (SDP)) to Proposed Standard


The IESG has received a request from the Multiparty Multimedia Session
Control WG (mmusic) to consider the following document: - 'Unknown Key Share
Attacks on uses of TLS with the Session Description
  Protocol (SDP)'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2019-06-19. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  This document describes unknown key-share attacks on the use of
  Datagram Transport Layer Security for the Secure Real-Time Transport
  Protocol (DTLS-SRTP).  Similar attacks are described on the use of
  DTLS-SRTP with the identity bindings used in Web Real-Time
  Communications (WebRTC) and SIP identity.  These attacks are
  difficult to mount, but they cause a victim to be mislead about the
  identity of a communicating peer.  Simple mitigation techniques are
  defined for each.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-mmusic-sdp-uks/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-mmusic-sdp-uks/ballot/


No IPR declarations have been submitted directly on this I-D.




2019-06-05
05 Cindy Morgan IESG state changed to In Last Call from Last Call Requested
2019-06-05
05 Adam Roach Last call was requested
2019-06-05
05 Adam Roach Last call announcement was generated
2019-06-05
05 Adam Roach Ballot approval text was generated
2019-06-05
05 Adam Roach Ballot writeup was generated
2019-06-05
05 Adam Roach AD Review is at https://mailarchive.ietf.org/arch/msg/mmusic/9ezwC218CghvH454X_qjOarXQRo
2019-06-05
05 Adam Roach IESG state changed to Last Call Requested from Publication Requested
2019-06-05
05 Bo Burman
As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated …
As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

A Proposed Standard RFC is being requested. The document specifies normatively mitigation techniques for key-share attacks on the use of Datagram Transport Layer Security for the Secure Real-Time Transport Protocol (DTLS-SRTP). The title page indicates "Standards Track".


(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary

  Relevant content can frequently be found in the abstract
  and/or introduction of the document. If not, this may be
  an indication that there are deficiencies in the abstract
  or introduction.

This document describes unknown key-share attacks on the use of
Datagram Transport Layer Security for the Secure Real-Time Transport
Protocol (DTLS-SRTP).  Similar attacks are described on the use of
DTLS-SRTP with the identity bindings used in Web Real-Time
Communications (WebRTC) and SIP identity.  These attacks are
difficult to mount, but they cause a victim to be mislead about the
identity of a communicating peer.  Simple mitigation techniques are
defined for each.


Working Group Summary

  Was there anything in WG process that is worth noting? For
  example, was there controversy about particular points or
  were there decisions where the consensus was particularly
  rough?

No.

Document Quality

  Are there existing implementations of the protocol? Have a
  significant number of vendors indicated their plan to
  implement the specification? Are there any reviewers that
  merit special mention as having done a thorough review,
  e.g., one that resulted in important changes or a
  conclusion that the document had no substantive issues? If
  there was a MIB Doctor, Media Type or other expert review,
  what was its course (briefly)? In the case of a Media Type
  review, on what date was the request posted?

The document was reviewed and discussed by a small group of key MMUSIC and RTCWEB members. No implementations are known.

Personnel

  Who is the Document Shepherd? Who is the Responsible Area
  Director?

The Document Shepherd is Bo Burman.
The Responsible AD is Adam Roach.

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

The document shepherd read the submitted version of the document fully and found no problems.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

There are no concerns. The described attacks and mitigations are rather intricate, but received careful review from a handful of experts in the field and the submitted text addresses all received comments.

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

No.

(6) Describe any specific concerns or issues that the Document Shepherd
has with this document that the Responsible Area Director and/or the
IESG should be aware of? For example, perhaps he or she is uncomfortable
with certain parts of the document, or has concerns whether there really
is a need for it. In any event, if the WG has discussed those issues and
has indicated that it still wishes to advance the document, detail those
concerns here.

No concerns.

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

The authors have confirmed that they do not know of any IPR disclosures that would be required.

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

No IPR disclosures have been filed.

(9) How solid is the WG consensus behind this document? Does it
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it? 

A handful of interested people (except the authors) have commented on the draft in MMUSIC and all those comments are addressed in the submitted draft.

(10) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarise the areas of conflict in separate
email messages to the Responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

There are no idnits, except for RFC 6234 being identified as a downref, which should be OK and RFC 6234 is already in the downref registry.

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

Not applicable.

(13) Have all references within this document been identified as
either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative
references exist, what is the plan for their completion?

This document has no normative references that are not ready for advancement:
* draft-ietf-mmusic-dtls-sdp; in RFC Ed queue MISSREF.
* draft-ietf-rtcweb-security-arch; in IESG Evaluation

(15) Are there downward normative references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

Yes, RFC 6234 (already in DOWNREF registry).

(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

The document updates RFC 8122, which is appropriately indicated.

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

The document shepherd reviewed the IANA section and its relation to and consistency with the document body, and found no issues. The suggested modifications of the existing IANA "TLS ExtensionType Values" registry are clearly described and consistent with current registry content.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

Not applicable.

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

Not applicable.
2019-06-05
05 Bo Burman Responsible AD changed to Adam Roach
2019-06-05
05 Bo Burman IETF WG state changed to Submitted to IESG for Publication from WG Consensus: Waiting for Write-Up
2019-06-05
05 Bo Burman IESG state changed to Publication Requested from I-D Exists
2019-06-05
05 Bo Burman IESG process started in state Publication Requested
2019-06-05
05 Bo Burman
As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated …
As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

A Proposed Standard RFC is being requested. The document specifies normatively mitigation techniques for key-share attacks on the use of Datagram Transport Layer Security for the Secure Real-Time Transport Protocol (DTLS-SRTP). The title page indicates "Standards Track".


(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary

  Relevant content can frequently be found in the abstract
  and/or introduction of the document. If not, this may be
  an indication that there are deficiencies in the abstract
  or introduction.

This document describes unknown key-share attacks on the use of
Datagram Transport Layer Security for the Secure Real-Time Transport
Protocol (DTLS-SRTP).  Similar attacks are described on the use of
DTLS-SRTP with the identity bindings used in Web Real-Time
Communications (WebRTC) and SIP identity.  These attacks are
difficult to mount, but they cause a victim to be mislead about the
identity of a communicating peer.  Simple mitigation techniques are
defined for each.


Working Group Summary

  Was there anything in WG process that is worth noting? For
  example, was there controversy about particular points or
  were there decisions where the consensus was particularly
  rough?

No.

Document Quality

  Are there existing implementations of the protocol? Have a
  significant number of vendors indicated their plan to
  implement the specification? Are there any reviewers that
  merit special mention as having done a thorough review,
  e.g., one that resulted in important changes or a
  conclusion that the document had no substantive issues? If
  there was a MIB Doctor, Media Type or other expert review,
  what was its course (briefly)? In the case of a Media Type
  review, on what date was the request posted?

The document was reviewed and discussed by a small group of key MMUSIC and RTCWEB members. No implementations are known.

Personnel

  Who is the Document Shepherd? Who is the Responsible Area
  Director?

The Document Shepherd is Bo Burman.
The Responsible AD is Adam Roach.

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

The document shepherd read the submitted version of the document fully and found no problems.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

There are no concerns. The described attacks and mitigations are rather intricate, but received careful review from a handful of experts in the field and the submitted text addresses all received comments.

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

No.

(6) Describe any specific concerns or issues that the Document Shepherd
has with this document that the Responsible Area Director and/or the
IESG should be aware of? For example, perhaps he or she is uncomfortable
with certain parts of the document, or has concerns whether there really
is a need for it. In any event, if the WG has discussed those issues and
has indicated that it still wishes to advance the document, detail those
concerns here.

No concerns.

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

The authors have confirmed that they do not know of any IPR disclosures that would be required.

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

No IPR disclosures have been filed.

(9) How solid is the WG consensus behind this document? Does it
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it? 

A handful of interested people (except the authors) have commented on the draft in MMUSIC and all those comments are addressed in the submitted draft.

(10) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarise the areas of conflict in separate
email messages to the Responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

There are no idnits, except for RFC 6234 being identified as a downref, which should be OK and RFC 6234 is already in the downref registry.

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

Not applicable.

(13) Have all references within this document been identified as
either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative
references exist, what is the plan for their completion?

This document has no normative references that are not ready for advancement:
* draft-ietf-mmusic-dtls-sdp; in RFC Ed queue MISSREF.
* draft-ietf-rtcweb-security-arch; in IESG Evaluation

(15) Are there downward normative references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

Yes, RFC 6234 (already in DOWNREF registry).

(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

The document updates RFC 8122, which is appropriately indicated.

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

The document shepherd reviewed the IANA section and its relation to and consistency with the document body, and found no issues. The suggested modifications of the existing IANA "TLS ExtensionType Values" registry are clearly described and consistent with current registry content.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

Not applicable.

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

Not applicable.
2019-06-04
05 Martin Thomson New version available: draft-ietf-mmusic-sdp-uks-05.txt
2019-06-04
05 (System) New version approved
2019-06-04
05 (System) Request for posting confirmation emailed to previous authors: Eric Rescorla , Martin Thomson
2019-06-04
05 Martin Thomson Uploaded new revision
2019-06-04
05 Martin Thomson Uploaded new revision
2019-05-22
04 Bo Burman Tag Revised I-D Needed - Issue raised by WGLC cleared.
2019-05-22
04 Bo Burman IETF WG state changed to WG Consensus: Waiting for Write-Up from In WG Last Call
2019-05-07
04 Martin Thomson New version available: draft-ietf-mmusic-sdp-uks-04.txt
2019-05-07
04 (System) New version approved
2019-05-07
04 (System) Request for posting confirmation emailed to previous authors: Eric Rescorla , Martin Thomson
2019-05-07
04 Martin Thomson Uploaded new revision
2019-05-07
04 Martin Thomson Uploaded new revision
2019-04-01
03 Bo Burman Tag Revised I-D Needed - Issue raised by WGLC set.
2019-01-07
03 Flemming Andreasen IETF WG state changed to In WG Last Call from WG Document
2019-01-07
03 Flemming Andreasen Changed consensus to Yes from Unknown
2019-01-07
03 Flemming Andreasen Intended Status changed to Proposed Standard from Informational
2019-01-03
03 Martin Thomson New version available: draft-ietf-mmusic-sdp-uks-03.txt
2019-01-03
03 (System) New version approved
2019-01-03
03 (System) Request for posting confirmation emailed to previous authors: Martin Thomson , mmusic-chairs@ietf.org, Eric Rescorla
2019-01-03
03 Martin Thomson Uploaded new revision
2018-08-07
02 Martin Thomson New version available: draft-ietf-mmusic-sdp-uks-02.txt
2018-08-07
02 (System) New version approved
2018-08-07
02 (System) Request for posting confirmation emailed to previous authors: Martin Thomson , Eric Rescorla
2018-08-07
02 Martin Thomson Uploaded new revision
2018-08-07
02 Martin Thomson Uploaded new revision
2018-08-03
01 (System) Document has expired
2018-01-30
01 Martin Thomson New version available: draft-ietf-mmusic-sdp-uks-01.txt
2018-01-30
01 (System) New version approved
2018-01-30
01 (System) Request for posting confirmation emailed to previous authors: Martin Thomson , Eric Rescorla
2018-01-30
01 Martin Thomson Uploaded new revision
2018-01-30
01 Martin Thomson Uploaded new revision
2017-08-31
00 Bo Burman Notification list changed to Bo Burman <bo.burman@ericsson.com>
2017-08-31
00 Bo Burman Document shepherd changed to Bo Burman
2017-08-03
00 Bo Burman Intended Status changed to Informational from None
2017-08-03
00 Bo Burman This document now replaces draft-thomson-mmusic-sdp-uks instead of None
2017-08-01
00 Martin Thomson New version available: draft-ietf-mmusic-sdp-uks-00.txt
2017-08-01
00 (System) WG -00 approved
2017-07-31
00 Martin Thomson Set submitter to "Martin Thomson ", replaces to (none) and sent approval email to group chairs: mmusic-chairs@ietf.org
2017-07-31
00 Martin Thomson Uploaded new revision