1447192 - DigiCert: Onion Certs

Status: RESOLVED FIXED

(CA Program :: CA Certificate Compliance, task)

Description

[Jeremy Rowley]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36

Steps to reproduce:

1. How your CA first became aware of the problem (e.g. via a problem report submitted to your Problem Reporting Mechanism, via a discussion in mozilla.dev.security.policy, or via a Bugzilla bug), and the date.

We received an email from Alex Cohen on March 9, 2018. It was posted to the Mozilla list the next day
   
2.  A timeline of the actions your CA took in response.

a) 3/9/3018- Received an email from Alex cohen about the impacted certificates
b) 3/10/2018 - Revoked the certificates
c) 3/12/2018- Scanned database for any additional certificates. All identified certificates were revoked 
d) 3/12/2018 - Alex posted information to Mozilla list, and Jeremy responded on what happened.
e) 3/14/2018 - Added error handling to detect when a tor descriptor is missing

Still to do: Add error handling to check that the cert has sufficient tor descriptors - 1 per onion name.
     
3.  Confirmation that your CA has stopped issuing TLS/SSL certificates with the problem.
DigiCert has stopped issuing onion certs that lack a descriptor
    
4.  A summary of the problematic certificates. For each problem: number of certs, and the date the first and last certs with that problem were issued.
20 certificates, all logged to CT, ranging from Oct 2017 to Mar 2018 

5.  The complete certificate data for the problematic certificates. The recommended way to provide this is to ensure each certificate is logged to CT and then list the fingerprints or crt.sh IDs, either in the report or as an attached spreadsheet, with one list per distinct problem.
https://crt.sh/?q=240277340 (revoked 26 October 2017)
https://crt.sh/?q=261570255
https://crt.sh/?q=261570338
https://crt.sh/?q=261570380
https://crt.sh/?q=261570384
https://crt.sh/?q=261579788
https://crt.sh/?q=261601212
https://crt.sh/?q=261601280
https://crt.sh/?q=261601281
https://crt.sh/?q=261601284
https://crt.sh/?q=261988060
https://crt.sh/?q=326491168
https://crt.sh/?q=326830043
https://crt.sh/?q=328308725
https://crt.sh/?q=328961187
https://crt.sh/?q=329559222
https://crt.sh/?q=330180704
https://crt.sh/?q=351449233
https://crt.sh/?id=351449246
    
6.  Explanation about how and why the mistakes were made or bugs introduced, and how they avoided detection until now.

> Looking into this, we did not correctly implement the ballot:
> 1. We didn't add a check to our backend system too verify the cert 
> included a descriptor prior to issuance.
> 2. On the front end, we missed requiring a Tor descriptor prior to 
> processing the order.
> 3. The validation team received insufficient training on the Tor 
> descriptor requirement.

In reality, the issue was too much reliance on the human component of asserting the Tor descriptors instead of having a technical control in place. We have a central system that manages compliance. The checks for onion certs were never added to this system. They exist now but only to ensure a tor descriptor exists. We are still working on adding checks to ensure at least one descriptor exists for each onion name.


7.  List of steps your CA is taking to resolve the situation and ensure such issuance will not be repeated in the future, accompanied with a timeline of when your CA expects to accomplish these things.

We revoked the certificates and added preliminary checking for Tor descriptors. We are adding additional checks to ensure certs cannot issue without them.

Comment 1

[Wayne Thayer]

Jeremy: thanks for filing this bug. Please provide an update when the technical controls are in place, and provide a date if that work will take some time to complete.

Comment 2

[Wayne Thayer]

Jeremy: has all of the remediation work described above been completed?

Comment 3

[Jeremy Rowley]

Yes. We added all technical controls, revoked all certs that were issued after the effective date of the new ballot, and added additional training to the staff. I think everything is re-mediated.