Get Permission Email security vendor Mimecast confirmed Tuesday that the hackers responsible for the SolarWinds supply chain hack also breached the security firm's network to compromise a digital certificate that encrypts data that moves between some of the firm's products and Microsoft's servers. When London-based Mimecast first acknowledged the breach earlier this month, the company reported that fewer than 10 of its clients had been targeted by the hackers during the compromise. The company is urging affected customers in the U.S. and U.K. to break and reestablish their connections to Microsoft products with newly issued keys, according to the update.