DigiCert: Underscore character certificates

This case concerns DigiCert certificates containing underscore characters. The issue was raised by browsers on the CA/Browser Forum on September 5, 2018, and DigiCert’s internal and CAB Forum discussions indicated that browsers believed the underscore-containing certificates were mis-issued and might require revocation. In response, DigiCert ceased issuance of underscore characters on October 1, 2018, notified customers about the browser concern, and conducted internal discussions and customer impact discussions. DigiCert gathered data on impacted certificates across systems and later noticed the data was wrong and regathered the information. The thread indicates that DigiCert would create separate bugs for each affected customer, and this bug was marked as a duplicate of bug 1515788. The bug’s resolution is DUPLICATE and the thread was closed accordingly.

1. 2018-09-05 Browsers raised an issue on the CA/Browser Forum regarding underscore character certificates.
2. 2018-10-01 DigiCert ceased issuance of certificates containing underscore characters.
3. 2018-11-09 Voting period ended for the CAB Forum ballot indicating a requirement to revoke the certificates.
4. 2018-12-21 The bug was closed as a duplicate because DigiCert would file separate bugs per affected customer.

1. 2018-12-20 DigiCert — Provided a detailed timeline of how DigiCert became aware of the underscore issue, actions taken (including ceasing issuance and customer notifications), and internal steps related to the CAB Forum ballot and revocation requirement.
2. 2018-12-20 DigiCert — Created an attachment (underscore.xlsx).
3. 2018-12-20 Fastly representative — Pointed to a related discussion thread at https://groups.google.com/d/msg/mozilla.dev.security.policy/0oy4uTEVnus/pnywuWbmBwAJ.
4. 2018-12-21 Fastly representative — Closed this bug because DigiCert would create separate bugs per affected customer and marked this bug as a duplicate of bug 1515788.