Isophoric News · Sunday, October 18, 2026
ConnectWise shuts Cloud Backup after attackers compromise Microsoft 365 tenants
ConnectWise has shut down customer access to its Cloud Backup service after hackers used the service's application identities to compromise Microsoft 365 tenants, BleepingComputer reported. Security firm Huntress said it identified at least 162 compromised tenants in its environment, and Microsoft said it saw unauthorized authentication attempts from one IP address on Oct. 15; the full victim count and the extent of any data theft are unclear. ConnectWise says it has no indication that stored backup data was compromised and that existing archives are isolated, and as of its Oct. 18 update scheduled backups were not running and restoration remained unavailable. ConnectWise, Microsoft and Huntress each advise administrators to review the application's sign-ins and credentials in their Microsoft 365 tenants for unexpected activity or additions.
