Mimecast, company cyber security that helps thousands organizations worldwide to make them safer e-mail, to restore trust and strengthen cyber resilience, revealed a security incident on January 12, warning customers that an "advanced" group of hackers has acquired one of the digital CERTIFICATES and abused it to obtain access in Microsoft 365 customer accounts. The London-based company said the certificate was used by many of them products her for connection with Microsoft infrastructure.
Mimecast noted that approximately 10% of its customers use the affected products with this particular certificate. However, "sophisticated" hackers misused the stolen certificate to gain access to only a few Microsoft 365 accounts of these customers.
According to ZDNet, the company estimates that the number of these accounts does not exceed 10, describing it as a "low single digit number", adding that it has already contacted all those affected customers.
To prevent future misuse, the company is now asking all of its customers to immediately delete the existing connection to their Microsoft 365 tenant and proceed to a new certificate-based connection using the new certificate available.
In addition, Mimecast said it is currently working with a third-party expert, Microsoft and law enforcement, to investigate how the security incident occurred and what the consequences might be.
The company said it was informed of the incident by Microsoft after the tech giant detected unauthorized access to certain accounts.
Scenarios are heard that this security incident may be related to its recent hack Solarwinds. However, when asked, a Mimecast spokesman declined to comment.