Microsoft Was Routing Example-Domain Traffic To a Japanese Cable Company for Five Years

Microsoft has quietly suppressed an unexplained anomaly on its network that was routing traffic destined for example.com -- a domain reserved under RFC2606 specifically for testing purposes and not obtainable by any party -- to sei.co.jp, a domain belonging to Japanese electronics cable maker Sumitomo Electric.
The misconfiguration meant anyone attempting to set up an Outlook account using an example.com email address could have inadvertently sent test credentials to Sumitomo Electric's servers.