Incident Report - 2020-10-26
On October 26, 2020, at 1:57 pm EDT, Duo’s Engineering Team was made aware of an issue with on-premises Active Directory syncs that resulted in some customers’ syncs failing to run. Customers on the following deployments were potentially affected: DUO38, DUO64, DUO55, and DUO66.
These failures resulted in some new users being unable to authenticate with Duo. Additionally, users who were supposed to be removed from Duo via directory sync may not have been removed as intended. After this issue was resolved, subsequent directory syncs added and removed users as intended.
The root cause of this error was determined to be a bug introduced in Duo’s late October release, which began deploying to customers at 11:00 am EDT on October 26, 2020. This bug was introduced during updates to Duo’s directory sync code to remove reliance on a deprecated library.
A fix for the issue was added to the release and redeployed to all affected customers. This was finished by 5:24 pm EDT on October 26. Duo’s Engineering Team has enhanced automated test coverage in this area to prevent this issue in the future.