Tony Redmond reports:
The danger of making mistakes when changing cloud systems that run at massive scale was demonstrated on Thursday evening (August 3) when the Office 365 Admin Center suddenly started to reveal usage data belonging to other tenants. Reports flooded in from administrators who noticed that the reported email and SharePoint usage for their tenants had spiked enormously When they went to look at the underlying data, they saw that it included users from one or more domains outside their tenant. The breach revealed names and email addresses of those users.
The problem surfaced in multiple Office 365 datacenter regions, including both the U.S. and EMEA.
Read more on Petri. Redmond points out that in the grand scheme of things, this was not a huge breach, but under the EU General Data Protection Regulations that come into effect, this type of thing could be a big problem for Microsoft or other firms.