Alice Wonder | 20 Apr 19:02 2015
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Suggestions for Fixing PKI

Dear List,

This is just for thought, I have neither the resources nor energy to 
push it through.

I would use the existing DNS system to do the equivalent of OCSP stapling.

ICANN creates a new TLD, we can call it pki.

Only certificate authorities can register names in pki.

The registry `Example Certificates, LTD.' would register example.pki

Even though the system uses the DNS system, only a limited subset of RR 
types would be allowed in the pki. TLD.

For example, MX and A and AAAA records etc. should not be allowed, it is 
a utility TLD intended to serve as infrastructure.

For the serial number in the SOA record, seconds since UNIX epoch would 
be what I would suggest. As serial is 32-bit that will eventually wrap 
but DNS allows for serial to wrap. Whether it is seconds since UNIX 
epoch or something else doesn't matter but I do suggest the serial be 
standardized, and YYYYMMDDnn does not allow enough updates in a 24 hour 
period.

BIND etc. probably shouldn't be used for the master, the master should 
probably be a custom server that talks to the CA's database and probably 
shouldn't have a public facing IP address, but bind / NSD / whatever 
could serve as slaves, there is no need for non-standard RR types to be 
(Continue reading)

Tobias Gondrom | 15 Apr 17:22 2015

FYI: presentation about HSTS and key pinning adoption at last IETF 92 SAAG meeting

Hi guys,

just fyi: there was 2 weeks ago an interesting presentation at the IETF 
92 SAAG about HSTS and key pinning adoption. If you are interested you 
can watch it here:

http://recordings.conf.meetecho.com/Playout/watch.jsp?recording=IETF92_SAAG&chapter=chapter_0 
(you can jump to minute 24 and play).

Best regards, Tobias

Phillip Hallam-Baker | 9 Apr 00:00 2015

DNS publication of HSTS and PKP header data using CAA

http://tools.ietf.org/html/draft-hallambaker-webseccaa-00

It is a pretty straightforward proposal:

* Use the CAA record with either the hsts or hpkp tag
* Put the same text you would have put into the CAA record value field

There are a few differences in interpretation. All we are trying to do
here is to help people to close the 'secure after first use' hole, not
replace.

Given that we have quite a bit of use of HSTS headers, providing a
mechanism for publishing this in the DNS looks like being the obvious
approach.

Tom Ritter | 19 Jan 18:55 2015

Requiring OCSP Stapling as a directive in HSTS

Hi all.  I'd like to propose an idea: add an optional directive to the
HSTS header that, when included, mandates any certificate received for
a domain require OCSP Stapling. It would respect includeSubdomains and
max-age.

The threat model I'm trying to address is an attacker who can get a
valid certificate misissued for a domain.  Because of the revocation
situation, the attacker can then MITM users with impunity, blocking
revocation lookups if they occur.  While UAs would receive a crlset or
other push of revoked certificates, I believe that the UA will still
work if that connection is blocked, and it's not clear how long that
connection must be blocked before the UA stops working entirely.  (If
that happens at all.)

Counting from the detection of the attack (which efforts like CT and
Pinning help detect), requiring OCSP stapling changes the window of
attack from {forever?, 30 days?, an unknown value?} to the OCSP
staple's lifetime.  (Assuming the attacker gets a OCSP signature right
before revocation.)

Why OCSP stapling and not require the UA to instead use 'hard-fail'
revocation checking?  Well, CRLs have all sorts of drawbacks: longer
expiry times, large sizes, and they're pretty much being phased out
everywhere.  (I know about Delta-CRLs - developing a specification for
them, implementing, and deploying them will take years, if ever, due
to IPR stuff. This does not.)   What about requiring OCSP querying?
Browsers don't much care for that - it's slow, can timeout for
non-security reasons, it's out of the control of the web site owner.
That leaves us with OCSP Stapling - it's fast, implemented, deployed.

(Continue reading)

=JeffH | 13 Jan 19:36 2015

test pls ignore

test

Chris Hartmann | 12 Jan 20:18 2015
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Authentic inter-domain relationships. Is this a security problem? Appropriate for websec?

1) Bob trusts and does personal business with a.com.

2) a.com forms a business relationship with b.com to perform a
business function on its behalf (payment processor, blog, whatever).
The landing page is b.com/a

3) Bob visits b.com/a and notices that the page claims to be
affiliated and owned by a.com

4) How can Bob, in absolute terms, trust that b.com/a is affiliated
and a delegated service by a.com? (say, prior to submitting sensitive
information)

Is this a security problem? I think so.

We’ve all had to make this decision one time or another on weak
inferences and correlations. I’d imagine Phishers don’t mind at all
that there is an inability for the common internet user (looking at
you grandma) to make the judgement call on web service affiliations.
They’ve been conditioned with the best practice of looking at the
address bar (and perhaps the DNS namespace) along with the lock icon
to indicate trustworthiness, which may actually help the attacker in
their act of misdirection. Inter-domain relationships model business
relationships and trust. If web users could be armed with a new
“sense” which proves these legitimate relationships (say
cryptographically) then perhaps they would have more reason to be
skeptical of those who cannot prove their affiliation. I’m not saying
we can take human judgement completely out of the equation, but why
not have a tool to help anchor this commonly needed and risky
correlation.
(Continue reading)

Jeffrey Walton | 2 Jan 06:21 2015
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Comments on draft-ietf-websec-key-pinning

I'd like to share some comments on
https://tools.ietf.org/html/draft-ietf-websec-key-pinning-21.

Pubic key pinning is an effective security control and I'm glad to see
the IETF moving forward with it. And I'm especially thankful to Palmer
and Sleevi for taking the time to put it together and shepherd it
through the process.

***** (1) *****

The title "Public Key Pinning Extension for HTTP" seems overly broad
and misses the mark a bit. The Abstract states its for User Agents,
but the title does not narrow focus.

There are different problem domains where public key pinning can be
utilized. Painting with a broad brush, I categorize them as "the
general problem" where no 'a priori' knowledge exists, and various
specific "instance problems", where 'a priori' does exits and can be
leveraged. An example of the general problem is browsers, and an
example of the instance problem is any custom software deployed by an
organization.

Suggestion: change the title to "Trust on First Use Pinsets and
Overrides for HTTP" or "Pinsets and Overrides for HTTP in User
Agents".

There are a few reasons for the suggestion. First, the abstract
effectively states its. Second, the proposed standard is a TOFU scheme
used for the general problem. Third, the Introduction recognizes the
two classes of problems when it discusses the pre-shared keys. Fourth,
(Continue reading)

Stephane Bortzmeyer | 17 Dec 14:56 2014
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[HSTS] Contradiction between sections 8.1 and 11.3 of RFC 6797?


[I'm not subscribed to the websec working group so please copy me when
replying.]

I don't know how to read section 11.3 of RFC 6797. It says "If all
four of the following conditions are true... [self-signed
certificates...]  ...then secure connections to that site will fail,
per the HSTS design." It seems to imply that adding a
Strict-Transport-Security: header to a site which has a self-signed
certificate is an error.

But section 8.1 says that the Strict-Transport-Security: will be
ignored if the HTTPS session is not secured (for instance because the
client uses a self-signed cert, section 8.1 says the header will be
accepted only "if there are no underlying secure transport errors or
warnings"). So, it seems that adding Strict-Transport-Security: is
useless (they will be ignored, per section 8.1) but not an error.

I checked with the Chromium browser "Version 20.0.1132.47 Ubuntu 12.04
(144678)" and a HTTPS site signed by CAcert.org (unknown CA for most
browsers) and, indeed, Chromium ignores the HSTS header and accepts to
use HTTP. Once CAcert.org cert is added, Chromium accepts the HSTS
header and uses only HTTPS. So, it seems the Chromium programmers
decided to ignore section 11.3?

Xiaoyin Liu | 7 Nov 07:56 2014

HSTS: Infinite max-age to address NTP spoofing attack?

 I recently read the slides "Bypassing HTTP Strict Transport Security" by
Jose Selvi.[1] It seems to me that one way to address NTP spoofing attack
on HSTS is to allow sites to specify HSTS policies that never expire (i.e.
infinite max-age), so that the enforcement of HSTS does not depend on the
system time.
 
So I want to propose a update to RFC 6797 to define a new directive called
"infinite" (or something else). When a UA sees this directive, max-age
should be ignored and HSTS should always be enforced until users clear the
cache or the server sends a valid STS header without "infinite" directive.
 
The new header field will look like:
  Strict-Transport-Security: max-age=31536000; infinite
 
Of course, many websites will be unwilling to set infinite max-age, so this
attack is not completely addressed. However, I think this new directive
should help a lot, because some websites, especially those that need to
send and receive sensitive information, such as online banking, are very
unlikely to revert to HTTP in the future. Also, a very long max-age, such
as 20 years used by Twitter, is effectively infinite, but long max-age is
subject to the NTP attack, while an explicit "infinite" is not.
 
Any comments on this? Thanks!
 
Best,
Xiaoyin
[1] https://www.blackhat.com/docs/eu-14/materials/eu-14-Selvi-Bypassing-HTTP-Strict-Transport-Security-wp.pdf
<div><div dir="ltr">&nbsp;I recently read the slides "Bypassing HTTP Strict Transport Security" by <br>Jose Selvi.[1] It seems to me that one way to address NTP spoofing attack <br>on HSTS is to allow sites to specify HSTS policies that never expire (i.e. <br>infinite max-age), so that the enforcement of HSTS does not depend on the <br>system time.<br>&nbsp;<br>So I want to propose a update to RFC 6797 to define a new directive called <br>"infinite" (or something else). When a UA sees this directive, max-age <br>should be ignored and HSTS should always be enforced until users clear the <br>cache or the server sends a valid STS header without "infinite" directive.<br>&nbsp;<br>The new header field will look like:<br>&nbsp; Strict-Transport-Security: max-age=31536000; infinite<br>&nbsp;<br>Of course, many websites will be unwilling to set infinite max-age, so this <br>attack is not completely addressed. However, I think this new directive <br>should help a lot, because some websites, especially those that need to <br>send and receive sensitive information, such as online banking, are very <br>unlikely to revert to HTTP in the future. Also, a very long max-age, such <br>as 20 years used by Twitter, is effectively infinite, but long max-age is <br>subject to the NTP attack, while an explicit "infinite" is not.<br>&nbsp;<br>Any comments on this? Thanks!<br>&nbsp;<br>Best,<br>Xiaoyin<br>[1] <a href="https://www.blackhat.com/docs/eu-14/materials/eu-14-Selvi-Bypassing-HTTP-Strict-Transport-Security-wp.pdf">https://www.blackhat.com/docs/eu-14/materials/eu-14-Selvi-Bypassing-HTTP-Strict-Transport-Security-wp.pdf</a><br>
</div></div>
Anne van Kesteren | 29 Oct 19:55 2014
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HSTS at DNS level

Is there some way we could add an annotation to DNS that makes it
clear a given domain for the purposes of HTTP is only available over
port 443 using TLS? DNS can be easily spoofed of course so you also
want HSTS, but perhaps it would be sufficient to be able to disable
port 80 entirely.

--

-- 
https://annevankesteren.nl/

Hodges, Jeff | 17 Oct 02:22 2014
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wrt closing the websec WG (was: DISCUSS positions on draft-ietf-websec-key-pinning

On 10/11/14, 1:03 PM, "Barry Leiba" <barryleiba <at> computer.org> wrote:

>  The working group will officially remain open until the RFC is
>published, after which I'll close it, but will leave the mailing list
>open for any continued discussion.

Yes, please do leave the mailing list open, the Web is a percolating pot
and there may well be more protocol-level security stuff boiling over into
IETF territory (I don’t have a firm example right now, but something along
the lines of defining more generic policy-expression format(s) is not hard
to imagine), and so perhaps similar to what we did with HTTP-State, who
knows, we might have a need to re-spin it up.

Thanks,

=JeffH

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