Security researchers are warning that threat actors could hijack Office 365 accounts to encrypt for a ransom the files stored in SharePoint and OneDrive services that companies use for cloud-based collaboration, document management and storage. A ransomware attack targeting files on these services could have severe consequences if backups aren’t available, rendering important data inaccessible to owners and working groups.
Link: Microsoft Office 365 feature can help cloud ransomware attacks
via http://www.bleepingcomputer.com