Microsoft confirms that Several Microsoft services, such as Azure App Services, Application Insights, Azure IoT Central, Azure Log Search Alerts, Azure Policy, and the Azure interface, were negatively impacted by a global outage caused on July 30, 2024, by a Distributed Denial-of-Service (DDoS) attack.
The event also affected another subset of Microsoft 365 and Microsoft Purview services.
Between 11:45 UTC and 19:43 UTC, an unexpected usage spike caused Azure Front Door (AFD) and Azure Content Delivery Network (CDN) components to perform below acceptable thresholds, resulting in:
- Intermittent errors
- Timeout issues
- Latency spikes
Although the DDoS protection mechanisms were activated, an error in implementing these defenses amplified the impact of the attack instead of mitigating it.
Microsoft's response team investigated the issue and implemented the following measures:
- Networking configuration changes to support DDoS protection efforts
- Failovers to alternate networking paths to provide relief
- Updated mitigation approach, rolled out across regions in Asia Pacific, Europe, and the Americas
The initial network configuration changes successfully mitigated most of the impact by 14:10 UTC. However, some customers reported less than 100% availability, which 18:00 UTC addressed. 19:43 UTC mitigated the incident, and failure rates returned to pre-incident levels.
Post-Incident Review and Next Steps
Microsoft will conduct an internal retrospective to understand the incident in more detail. The following reports will be published:
- Preliminary Post Incident Review (PIR) within approximately 72 hours
- Final Post Incident Review with additional details and learnings within 14 days
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