Mimecast for Microsoft 365 hacked

Get a free Techzine subscription!

Mimecast, a company dedicated to the management and security of Microsoft 365 products, has announced that one of its security certificates has been the target of a cyber attack.

The company said in a blog post that about 10 percent of its customers were using the compromised certificate. Less than ten customers were specifically targeted by the attack.

Leaked emails

Through the hack, the attackers could take over a Mimecast connection and read and even modify encrypted data. In this case, specifically, incoming and outgoing emails were intercepted. The hack can also be used to gain access to other data in Microsoft Exchange Web Services.

Mimecast advises affected customers to immediately delete existing connections to Microsoft 365 and reconnect with a new certificate. This will not affect the flow of email and security scans.

SolarWinds attackers

It is not known who is behind the attack. However, Saryu Nayyar, CEO of security firm Gurucul Solutions, told SiliconANGLE that he thinks it was the same attackers as those responsible for the SolarWinds hack. According to him, the attack is of a similar level of sophistication.