Microsoft said the outage that affected some of the company’s services earlier this month was the result of cyber attacks, but said it had seen no evidence of any user data being accessed or compromised.

“In early June 2023, Microsoft identified an increase in traffic against certain services that temporarily affected availability,” the company said in a blog post.

Microsoft said it launched an investigation and began tracking the DDoS activity of the threat actor it called Storm-1359 after identifying the threat.

Microsoft did not immediately respond to a Reuters request for information on whether the company had identified the party responsible for the attack.

DDoS attacks work by directing large volumes of Internet traffic to targeted servers in a relatively unsophisticated bid to knock them offline.

Microsoft’s 365 software suite, including Teams and Outlook, was down for more than two hours on June 5 for thousands of users and there was a brief resumption the next morning. It was the fourth such outage for Microsoft in a year.