"Midnight Blizzard"

Microsoft: Russian hackers also siphoned off emails

At the beginning of the year, Russian hackers landed a spectacular coup at the world's largest software manufacturer and were able to penetrate deep into Microsoft's corporate networks. It has now emerged that more data was siphoned off than expected.

According to Microsoft, emails from customers were also downloaded. "This week, we are continuing to notify customers who have corresponded with Microsoft corporate email accounts that were exported by the threat actor Midnight Blizzard," said a Microsoft spokesperson in an emailed statement.

Number of people affected unclear
Microsoft also said that it shared the compromised emails with its customers. However, the company did not specify how many customers were affected or how many emails may have been stolen.

These attacks and a Chinese hack last year prompted a congressional hearing earlier this month. The company is working to overhaul its security practices, Microsoft President Brad Smith said.

Russian state hackers
In January, the world's largest software provider had stated that Midnight Blizzard had accessed "a very small percentage" of the company's corporate email accounts. Four months later, Microsoft announced that the hackers were still trying to break in.

Midnight Blizzard is also referred to by cybersecurity researchers as APT29 or "Cozy Bear" and is associated with Russian intelligence services. The Russian government has not yet responded to the accusations of hacking against Microsoft.