Microsoft says early June disruptions to Outlook, cloud platform, were cyberattacks

In early June, sporadic but serious service disruptions plagued Microsoft's flagship office suite — including the Outlook email and OneDrive file-sharing apps — and cloud computing platform. A shadowy hacktivist group claimed responsibility, saying it flooded the sites with junk traffic in distributed denial-of-service attacks.

Initially reticent to name the cause, Microsoft has now disclosed that DDoS attacks by the murky upstart were indeed to blame.

A spokeswoman confirmed that the group that calls itself Anonymous Sudan was behind the attacks. It claimed responsibility on its Telegram social media channel at the time. Some security researchers believe the group to be Russian.

Serious impacts from the Microsoft 365 office suite interruptions were reported on Monday June 5, peaking at 18,000 outage and problem reports on the tracker Downdetector shortly after 11 a.m. Eastern time.

On Twitter that day, Microsoft said Outlook, Microsoft Teams, SharePoint Online and OneDrive for Business were affected.

Attacks continued through the week, with Microsoft confirming on June 9 that its Azure cloud computing platform had been affected.

On June 8, the computer security news site BleepingComputer.com reported that cloud-based OneDrive file-hosting was down globally for a time.