Microsoft outage: what happened and what does it say about online services?

Millions of people were unable to access their emails, Teams chats or meetings on Thursday night and Friday after a Microsoft 365 outage brought down services across the globe.The outage was into its second day on Friday, though Microsoft said it was seeing “encouraging recovery progress in Europe”. It affected businesses, government agencies and even Microsoft employees all over the world.The Health Service Executive said it had been affected by the global Microsoft outage, with emails not being transmitted.Those also reporting issues have included the US House of Representatives, an Australian spy agency, airlines in India, European government agencies, and police services, ambulances and hospitals in the UK. Microsoft is still investigating the cause of the outage, which it has said is not a cyberattack but a configuration error.Experts say that the outage has laid bare the dangerous dependence of countries on a few US tech companies. What happened and why?On Thursday, the outage website Down Detector showed an increase in users reporting issues with Microsoft 365, the suite of cloud software that includes Teams, Word Excel, PowerPoint and Outlook. By Friday morning, Microsoft had narrowed down most of the problems to Microsoft Exchange, the email service behind Outlook. Teams meetings and chats had returned to service. On Friday afternoon, Microsoft said there was “encouraging recovery progress in Europe”, improvements in North America and Asia Pacific, and Japan was “stable”.What caused the Microsoft outage?Microsoft has said that this was not the result of a cyberattack, though suspicions were high because of a number of cyberattacks that have hit organisations in Europe in recent weeks. So far, the problem appeared to be a configuration update that resulted in some servers becoming overloaded and taken offline, Microsoft indicated.When the company attempted to apply a fix, servers that had come back online again became unresponsive when traffic began returning to them.As some servers went down, traffic was funnelled on to the remaining servers, causing traffic problems for those remaining online.More details are likely to emerge over the coming weeks. “We don’t know what actually went wrong, and that will take weeks to discover,” said Steven Murdoch, a professor of security engineering at University College London. “The people who are working on it are too busy fixing to understand or report on the cause.” Why has Microsoft 365 been down for so long?An outage that runs for so long for a service as critical as Microsoft 365 is unusual. The company has not said why it has lasted this long, but a clue might be in its updates: as servers returned to being unresponsive after being fixed, engineers had to work through alternative solutions, taking longer than expected to get servers back up and running.What does the incident say about our reliance on online services?Experts have said that outages such as this underscored the world’s reliance on cloud services provided by a few large US tech companies – Amazon, Google and Microsoft. This reliance has been a growing source of unease through each high-profile outage. It has grown more pronounced because of the hostility of the Trump administration towards Europe, which has prompted some governments to consider alternatives to US software.As the name Microsoft 365 implies, the world has quickly become accustomed to online services being available 24/7. Given software is no longer solely downloaded to individual PCs but is also stored on a server owned by a company, outages such as this will happen. Most of the time they are brief but sometimes they are not.Outages in recent years from telecommunications providers, from the PHP incident to the CrowdStrike incident, show just how varied the sources and causes of a large outage can be. There are many different pieces of the puzzle keeping services online – but the effect of one of those services going down is much greater than it ever has been.Mark Gregory, an associate professor at Australia’s RMIT University, said it was important for organisations to thoroughly test updates before rolling them out to the live network. That was in addition to the extra security testing companies must carry out to ensure their services are protected from threat actors armed with AI tools that can find vulnerabilities quicker than ever before.Should we have backup options when services go down?Gregory said companies that relied on services such as Microsoft 365 should have backup options such as Google’s Gmail in the event of an outage. Others have suggested the free and open-source Office alternative LibreOffice.Around the world, it has become increasingly clear that many companies – and government services – do not have good backups, with businesses resorting to faxes and phones. – Guardian