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Fix typos
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aaaaalbert authored Jul 20, 2017
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Expand Up @@ -33,8 +33,8 @@ by](https://datatracker.ietf.org/doc/rfc5246/referencedby/) 434 other IETF
specifications, and is
[cited](https://scholar.google.com/scholar?q=http%3A%2F%2Fwww.hjp.at%2Fdoc%2Frfc%2Frfc5246.html&btnG=&hl=en&as_sdt=0%2C5)
by 3,281 publications in Google Scholar. Accepting any proposal that might
weaken such an important security protocol without due dilligence is utterly
unwise. And it is hard to see how anyone could really do that due dilligence
weaken such an important security protocol without due diligence is utterly
unwise. And it is hard to see how anyone could really do that due diligence
given the breadth of use of TLS today - both in openly specified foo/TLS
applications but also in the presumably larger number of not publicly
documented applications using TLS.
Expand All @@ -59,11 +59,11 @@ motivations, it's just a thing that we have to consider regardless.)
complexity of any "break TLS" proposal makes that situation worse, and
logically must do so. But we have more than argument to go on here - there is
evidence for this from peer-reviewed academic studies and examination of TLS
interception implmentations, for example [Durumeric et
al](https://www.internetsociety.org/sites/default/files/ndss2017_04A-4_Durumeric_paper.pdf)
interception implementations, for example [Durumeric et
al.](https://www.internetsociety.org/sites/default/files/ndss2017_04A-4_Durumeric_paper.pdf)
found that "that nearly all [interception proxies] reduce connection security
and many introduce severe vulnerabilities" whilst [de Carnavalet et
al](http://users.encs.concordia.ca/~mmannan/publications/ssl-interception-ndss2016.pdf)
al.](http://users.encs.concordia.ca/~mmannan/publications/ssl-interception-ndss2016.pdf)
performed a "systematic analysis uncovered that several of these tools severely
affect TLS security on their host machines." So, where there is evidence
publicly available, it seems to indicate that additional complexity (via
Expand All @@ -74,13 +74,13 @@ would lead to an overall improvement in security.
1. In many cases like this people also argue that even if breaking TLS is
undesirable, it's better to do that undesirable thing openly inside the IETF
as it would happen elsewhere in any case and perhaps be done worse. Without
specific evidence that organisation foo is about to take actionn bar, that
specific evidence that organisation foo is about to take action bar, that
argument is impossible to judge, so is at best neutral. When there is specific
evidence of something relevant being done elsewhere, then the IAB and IESG have
liaison mechaisms that can be used for the purpose for which they were
liaison mechanisms that can be used for the purpose for which they were
designed. IOW, "if we don't, they will" is not a good argument that the IETF
should do any particular thing at all. In the author's experience, this
argument is commonly assoociated with proponents of proposals that might be fairly
argument is commonly associated with proponents of proposals that might be fairly
described as being engaged in forum shopping. In the case of "break TLS"
proposals, one could argue (and I would) that the reason TLS is widely
used is, in significant part, because TLS is not broken.
Expand All @@ -94,7 +94,7 @@ here because we'd end up repeating almost all of it).
The IAB statement
recognises that increasingly widespread use of TLS causes issues
for network operations, but no response that amounts to attempting to break TLS
so far presented can be jusified due to the huge potential cost and impact
so far presented can be justified due to the huge potential cost and impact
of breaking TLS.

1. Most or all approaches to breaking TLS seem to involve changing TLS from a
Expand Down Expand Up @@ -146,13 +146,13 @@ in 2016, and [TLS-DIV](https://www.mitls.org/tls:div/) in 2017),
none of which
(to my knowledge) envisaged the use of static DH values, nor of centrally
generated DH values being "pushed" to many TLS servers. Similarly, work on the
TLS application layer PDU protection didn't envisge re-use of DH values in
TLS application layer PDU protection didn't envise re-use of DH values in
possibly many TLS sessions. Adoption of any work in this space could require
re-doing some of the analysis work, possibly delaying TLS1.3 or (worse)
resulting in new problems being found after widespread deployment. Given that
this draft would create new active and passive attack possibilities, such new
analysis work would seem to be required, especially if proprietary
extensions to the proposed "TSK" protocol affect the cryptogrphy used
extensions to the proposed "TSK" protocol affect the cryptography used
in TLS sessions.

- The work done by academic analyses of TLS1.3 has been valuable in terms
Expand Down Expand Up @@ -225,8 +225,8 @@ obsolete RFC2804, and are thus attempting an end-run
around IETF processes.

- To my knowledge, all wiretapping schemes
docuemted in RFC so far have been in the independent
stream (hence not IETF docuemts) or perhaps pre-date
documented in RFC so far have been in the independent
stream (hence not IETF documents) or perhaps pre-date
RFC streams.

- See below for more on this as a wiretapping
Expand Down Expand Up @@ -405,7 +405,7 @@ and claim (with the same evidence;-) that the opposite would eventuate.

1. This scheme enables active attacks - once the DH private values are known,
then all session keys are known and seemingly valid packets can be injected
into ongoing sessions. The abstract of the -01 draft is extermely misleading in
into ongoing sessions. The abstract of the -01 draft is extremely misleading in
claiming that it is for "passive monitoring." No mention is made in the draft
of the active attacks it enables.

Expand Down Expand Up @@ -457,7 +457,7 @@ values into a deployment.

1. [Section 7.2](https://tools.ietf.org/html/draft-green-tls-static-dh-in-tls13-01#section-7.2)
defines a key request interface, but defines no authorisation
scheme, no HTTP authentiction, and requires no additional CMS
scheme, no HTTP authentication, and requires no additional CMS
protection.
This creates an excellent target to attempt to find
when one has breached some network. That is an excellent
Expand All @@ -477,18 +477,18 @@ to exfiltrate the PSK as well." If correct, that would seem to
indicate that this proposal is broken.

1. The use of CMS means that there are already a vast array of possible (even
deployment-speciic) extension points in this protocol. That means that it is
deployment-specific) extension points in this protocol. That means that it is
not possible to have any confidence that what would be designed is what would
be deployed. In fact, given the detectability issues above, it seems very
likely that non-deection (meaning non-compliance with the putative RFC) will be
likely that non-detection (meaning non-compliance with the putative RFC) will be
a goal for implementers.

IMO none of the above ought not be fixed by IETF participants collectively.

#### Why is this wiretapping?

Some IETF TLS WG list participants have denied that this is a wiretapping
propospal, based on it somehow not matching the definitions in
proposal, based on it somehow not matching the definitions in
[RFC2804](https://tools.ietf.org/html/rfc2804).
Firstly, that is far too lawyerly and IMO being overly pedantic with the 2804
definitions. If one looks at Figure 3 in the draft, it very clearly matches any
Expand Down Expand Up @@ -527,7 +527,7 @@ even taking a lawyerly approach...
clearly allows that intermediate MTA to renege and leak
their private values and hence senders and recipients will
not get the confidentiality they expect. Note that SMTP/TLS
is almost ubiquituous today and that 2-TLS session setups
is almost ubiquitous today and that 2-TLS session setups
are common, e.g. if the intermediary MTA does AV scanning.
In this case, the relevant parties to the communication
(for the RFC2804 definition) are the mail senders and
Expand Down Expand Up @@ -558,7 +558,7 @@ confidentiality is sadly outdated.
<pre>

+-----------+ +--------------+ +----------+ +---------+ +-------------+
|mail sender+--+Submit serveer+--+---+AV scanner+-----+Recip MTA+--+mail receiver|
|mail sender+--+Submit server +--+---+AV scanner+-----+Recip MTA+--+mail receiver|
+-----------+ +--------------+ | +-----+----+ +---------+ +-------------+
| |
| |
Expand Down

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