CISA released a Microsoft Expanded Cloud Logs Implementation Playbook that I recommend Microsoft 365 administrators take a look at.
“This playbook provides an overview of the newly introduced logs in Microsoft Purview Audit (Standard), which enable organizations to conduct forensic and compliance investigations by accessing critical events, such as mail items accessed, mail items sent, and user searches in SharePoint Online and Exchange Online. In addition, the playbook also discusses significant events in other M365 services such as Teams. Lastly, administration/enabling actions and ingestion of these logs to Microsoft Sentinel and Splunk Security Information and Event Management (SIEM) systems are covered in detail.”
“Default enablement is defined at a license level. For example, Auditing (Standard or Premium) is enabled by default for E3/E5/G3/G5 licenses. Some licenses, such as M365 Business Basic, M365 Business Standard, M365 Business Premium, and trial license accounts do provide access to Audit but do not currently have auditing enabled by default. These licenses will have Audit enabled by default in the future. If you are leveraging one of these license types, the steps below can be utilized to ensure that all audit features are enabled.”
Thus, if you are using ANY Microsoft 365 license in my books you want to ensure all the logging available to you is enabled for all user, regardless of Microsoft does.
The playbook will take you what needs to be done. Most of it relates to:
Mailbox actions for user mailboxes and shared mailboxes
with the most important being around the MailItemsAccessed setting, but there are others.
The most important thing to remember is that most of these settings cannot be set in the web portal and can only be set using PowerShell commands like:
Set-Mailbox – @{Add=“SearchQueryInitiated”}
Apart from these settings the playbook has lots of additional handy information that will help with the security of your Microsoft 365 environment and this makes it a recommended read for all administrators.
CIAOPS 