[cabfpub] AIA chasing

J.C. Jones jc at mozilla.com
Mon Apr 3 19:10:08 UTC 2017

I'm afraid that hasn't been considered, as release of any of the data set
would require legal review.

Something I could audit and then run locally would be ideal. I've started
such a tool at https://github.com/jcjones/aia-chaser (and just made it
mostly work, I think), but it will take a little more time before I can
process the data with it.

Review is welcome.

On Mon, Apr 3, 2017 at 10:12 AM, Ryan Sleevi <sleevi at google.com> wrote:

> Considering that SSLLabs offers such a tool, has Mozilla considered
> reaching out to them to exercise a scan of the subset of hosts you're
> interested in, and sharing that data?
> On Mon, Apr 3, 2017 at 1:08 PM, J.C. Jones <jc at mozilla.com> wrote:
>> Ryan,
>> As mentioned in the bug discussion, it's not to be taken that 5.88% is
>> gospel, rather that it's 1) a very noisy indication of the effect fetching
>> would have on total errors, and 2) a call for interested community members
>> to help us do more with the data.
>> More sophisticated analysis is absolutely welcome; we have both the
>> certificate dataset and the hostname dataset which we can operate on. If
>> someone were interested in writing a tool that, given a host, would
>> determine whether AIA fetching would avoid a connection error, I'd be happy
>> to run it and provide the results to the community.
>> (Note to implementers, we'd need to probably provide Moz's trusted roots
>> as a configuration item, too)
>> Cheers,
>> J.C.
>> Crypto Engineering
>> On Mon, Apr 3, 2017 at 9:08 AM, Ryan Sleevi via Public <
>> public at cabforum.org> wrote:
>>> That is most unfortunate.
>>> It doesn't look like the code in https://gist.github.com/moz
>>> keeler/29754494dcdb3b169483595283f29923 fully accounts for the value of
>>> AIA with respect to finding alternative paths on such connections. That is,
>>> it seems like it undercounts for situations such as:
>>> Leaf -> Intermediate 1 -> Intermediate 2 -> Old CA
>>>         -> Intermediate 1 -> Intermediate 2' -> New CA
>>>         -> Intermediate 1' -> New CA
>>> The analysis Mozilla performed only appeared to examine the end-entity
>>> certificate, as noted in https://bugzilla.mozilla.or
>>> g/show_bug.cgi?id=399324#c80 . However, Chrome's experience with AIA is
>>> that it is most useful for covering the root key rollover and intermediate
>>> rollover scenarios. I can think of a number of CA members who have
>>> exercised this code path, but such data was excluded from your analysis.
>>> I appreciate you looking into this matter, though, and for ensuring the
>>> data and tools were publicly available in order to perform such an analysis.
>>> An alternative methodology to examine would be to examine the supplied
>>> chains from the subset of servers (or user error reports) for which you're
>>> interested in, and determine whether there exists a path to a known Mozilla
>>> trust anchor. For example, you could use the CCADB disclosures, crt.sh
>>> dataset (which handedly already groups by ca_id), or directly from
>>> Certificate Transparency log servers. For such situations where the server
>>> did not supply a path that immediately resolved, but one or more paths was
>>> known to Mozilla, you could examine whether or not the AIA identity
>>> provided by the common elements in that path (even if the only common
>>> element was the leaf) would have provided one or more intermediates known
>>> to be valid.
>>> I do hope you reconsider, because it does appear that the testing
>>> methodology was flawed.
>>> On Mon, Apr 3, 2017 at 10:51 AM, Gervase Markham via Public <
>>> public at cabforum.org> wrote:
>>>> Participants may be interested in some recent research we did on AIA
>>>> chasing:
>>>> https://bugzilla.mozilla.org/show_bug.cgi?id=399324#c80
>>>> The upshot is that Firefox has no plans to implement this feature.
>>>> Gerv
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