Security News > 2021 > January > Mimecast links security breach to SolarWinds hackers

Email security company Mimecast has confirmed today that the threat actor behind the SolarWinds supply-chain attack is behind the security breach it disclosed earlier this month.

"Our investigation has now confirmed that this incident is related to the SolarWinds Orion software compromise and was perpetrated by the same sophisticated threat actor," Mimecast said.

While the exact number of affected customers using the stolen certificates to secure the connection to the Microsoft 365 cloud was not disclosed, Mimecast said that roughly 10 percent of their customers "Use this connection."

Mimecast's products are currently used by more than 36,000 customers, with 10% of them amounting to roughly 3,600 impacted customers.

The company found evidence that "a low single-digit number of our customers' M365 tenants were targeted" by the SolarWinds hackers.

Mimecast reached out to these customers to remediate and address this issue and, according to today's update, "[t]he vast majority of these customers have taken this action, and Microsoft has now disabled use of the former connection keys for all affected Mimecast customers.

News URL

https://www.bleepingcomputer.com/news/security/mimecast-links-security-breach-to-solarwinds-hackers/