Re: [lamps] Warren Kumari's Block on charter-ietf-lamps-02-00: (with BLOCK and COMMENT)

Russ Housley <> Wed, 23 May 2018 21:18 UTC

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Date: Wed, 23 May 2018 17:18:31 -0400
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Subject: Re: [lamps] Warren Kumari's Block on charter-ietf-lamps-02-00: (with BLOCK and COMMENT)
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Please see my response at the bottom of the message ...

>> On May 23, 2018, at 3:31 PM, Warren Kumari < <>> wrote:
>> On Wed, May 23, 2018 at 1:39 PM Yoav Nir < <>> wrote:
>> Hi Warren.
>> Since it was my draft and presentation at SecDispatch that led to this item, I feel I can answer this.  Inline.
>> > On 23 May 2018, at 20:10, Warren Kumari < <>> wrote:
>> > 
>> > Warren Kumari has entered the following ballot position for
>> > charter-ietf-lamps-02-00: Block
>> > 
>> > When responding, please keep the subject line intact and reply to all
>> > email addresses included in the To and CC lines. (Feel free to cut this
>> > introductory paragraph, however.)
>> > 
>> > 
>> > 
>> > The document, along with other ballot positions, can be found here:
>> > <>
>> > 
>> > 
>> > 
>> > ----------------------------------------------------------------------
>> > BLOCK:
>> > ----------------------------------------------------------------------
>> > 
>> > "3. Specify the use of short-lived X.509 certificates for which no
>> > revocation information is made available by the Certification Authority.
>> > Short-lived certificates have a lifespan that is shorter than the time
>> > needed to detect, report, and distribute revocation information, as a
>> > result revoking them pointless."
>> > 
>> > This makes me twitch -- how short is "short”?
>> [YN] I expect this to be contentious within the working group, and I expect the exact cut-off point to be different from one use-case to another. For highly reliable systems with good clock synchronization “short” could be as low as an hour. For typical systems I think the likely lifetime will be between 1 day and 1 week.  IMHO it’s valid for the working group to leave the cut-off between “short” and “not short” to per-domain profiles, but I don’t think anything beyond 2 weeks would ever count as short.
>> > And how long is the time to
>> > "detect, report, and distribute revocation information"? With e.g: CT,
>> > misissued certificates may be visible before they are used in an attack,
>> > decreasing the detection time.
>> [YN] Someone needs to see the certificate to add it to the log, and someone needs to find the certificate on the log and understand that it is mis-issued. And then someone needs to add it to the CRL / database that feeds the OCSP responder. And when this is updated, relying parties may have cached copies of older revocation information. Add it up and it can take days on the web.  In closed environments there may not be CT at all.  
>> ​So, here you say: "Add it up and it can take days on the web." and above that you say: "For typical systems I think the likely lifetime will be between 1 day and 1 week.  [...] , but I don’t think anything beyond 2 weeks would ever count as short."
>> "1 week" minus "days" is still greater than zero, and so it still *seems* to me that removing revocation is a bad idea -- but, my role is (or should be!) to make sure that this charter doesn't conflict with other work (esp. ops work), that the charter "describes the specific problem or deliverables (a guideline, standards specification, etc.) it has been formed to address. WG charters state the scope of work for group, and lay out goals and milestones that show how this work will be completed." It is (IMO) the sponsoring ADs, the WGs and IETFs decision as to if the ideas themselves are acceptable.
>> I'm not (yet!) so arrogant that I'm sure I know the right answer to everything, so I'd like to discuss this with EKR on the call tomorrow, and will clear my block once I've been assured process is being followed
>> / this has been considered.
> Warren:
> I think the point you are missing is that it take time to process revocation and get the CRL published or OCSP responder updated.  This is always over a week because people do not revoke without doing due diligence.  So, letting the short-lived certificate expire without issuing a replacement will actually cause revocation to happen more quickly.
> ​I remain unconvinced -- some years ago I purchased a ​DV cert and, though a series of stupidly I managed to delete the private key[0]. The CA / reseller I was using had a friendly "Revoke" button which let me upload a new CSR and get a new cert within a few minutes. I'll happily admit that I didn't check if they actually added the old one to a CRL, a: I assumed that they did and b: they did let me reissue without more $$$ - which was the only bit I actually cared about :-).
> Now that I've finished writing this it feels somewhat like: "I just the other day got… an Internet was sent by my staff at 10 o'clock in the morning on Friday. I got it yesterday [Tuesday]. Why? Because it got tangled up with all these things going on the Internet commercially." - Ted Stevens.
> W
> [0]: ejabberd wants the key, cert and intermediate certs all in a single .pem file -- while trying to make this I managed to overwrite the key  (I did 'cp * >' instead of 'cat * >')

You needed a replacement certificate associated with a new key pair because the private key was lost.  You were not worried about someone else using the private key in a malicious manner.  I do not think this work item will make that easier or harder.