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. But the software giant has offered few details— and did not immediately comment on how many customers were affected and whether the impact was global. 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. Microsoft's explanation in a blog post on June 16 evening followed a request by The Associated Press two days earlier.