Microsoft confirmed that the recent outage last July 30 was caused by a distributed denial of service (DDOS) cyberattack, affecting several users.

The effect was felt across several Microsoft services including Microsoft 365, Office, Outlook, and Azure.

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Microsoft Addresses 10-Hour Outage After DDOS Cyberattack

The incident started around 11:45 a.m. UTC and was only resolved around 7:43 p.m. Microsoft stated that a subset of its customers may have experienced issues connecting to their services globally.

Affected services included Azure Policy, Azure Log Search Alerts, Azure App Services, Application Insights, Azure IoT Central, and the Azure portal. Some users also experienced some issues while working on Microsoft 365 and Microsoft Purview services.

The company quickly rolled out a mitigation approach and implemented networking configuration changes to support its DDOS protection security. The services are now fully back to normal according to the Azure Status history page.

Microsoft Experiences Unexpected Usage Spike

In a status update, the company detailed that the event was a result of an "unexpected usage spike" which led to some of its core services delivering below the expected performance. The issue also caused intermittent errors, timeout, and latency spikes.

The majority of tech companies have placed policies to prevent DDOS attacks from disrupting operations. Microsoft admitted that there was an error in the implementation of the security, causing the attack to amplify its effects to the users.

Microsoft announced that it would publish a post-incident report within 72 hours to provide more explanation about the incident. An internal retrospective would be put in place to assess the further actions that the company will take.

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