Authentication Issues
Incident Report for Duo Security

Between approximately 20:45 to 21:31 UTC (4:45 to 5:31 Eastern Time) on October 20, and 14:08 to 15:03 UTC (10:08 to 11:03 Eastern Time) on October 21, a significant number of users on Duo Security’s DUO1 deployment were unable to authenticate.

Several servers failed to process authentications. This led to intermittent cascading failures in which DUO1 servers processing authentications became overloaded and intermittently timed out. Our Operations Team was able to manually clear the backlogs causing this cascading failure and fully restore service between 21:20 to 21:31 UTC on October 20, and 14:56 to 15:03 UTC on October 21.

Because the recovery was implemented in stages, the total outage time depended on which applications were protected and authentication factors used.

We traced the outage to being the result of contention between user onboarding processes and backend cleanup procedures, and we are implementing architectural changes that will prevent future cascading failures and associated end user impact. As a reminder, you can subscribe to receive status updates related to your specific Duo deployment here at:

Posted about 2 years ago. Oct 21, 2015 - 16:27 EDT

Our operations team has confirmed that this issue is resolved, and a postmortem will be provided shortly.
Posted about 2 years ago. Oct 21, 2015 - 16:25 EDT
Our operations team has resolved the issue for now. We are continuing to monitor the situation to ensure it doesn't occur again.
Posted about 2 years ago. Oct 21, 2015 - 11:18 EDT
We are currently investigating reports of authentication issues. We will update with more specific information as it becomes available.
Posted about 2 years ago. Oct 21, 2015 - 10:59 EDT
This incident affected: DUO1 (Core Authentication Service).