A workbook is a data-driven interactive report in Microsoft Sentinel. You can use workbooks to create custom reports based on data from your Azure subscription. Reference: https://docs.microsoft.com/en-us/azure/sentinel/workbooks-overview

Reference:
https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/safe-attachments?view=o365-worldwide

Reference:
https://docs.microsoft.com/en-us/azure/security-center/defender-for-key-vault-usage

To identify which blobs were deleted, you should review the activity logs of the storage account. The activity logs contain information about all the operations that have taken place in the storage account, including delete operations. These logs can be accessed in the Azure portal by navigating to the storage account, selecting "Activity log" under the "Monitoring" section, and filtering by the appropriate time range. You can also use Azure Monitor and Log Analytics to query and analyze the activity logs data.
Reference:
https://docs.microsoft.com/en-us/azure/storage/common/storage-activity-logs
https://docs.microsoft.com/en-us/azure/azure-monitor/platform/activity-log-azure-storage

Potential malicious events: When traffic is detected from sources that are known to be malicious, Microsoft Sentinel alerts you on the map. If you see orange, it is inbound traffic: someone is trying to access your organization from a known malicious IP address. If you see Outbound (red) activity, it means that data from your network is being streamed out of your organization to a known malicious IP address.