When investigating suspicious activity in a user's account in Azure Sentinel, what is the most important first step?

The initial step when investigating suspicious activity in a user's account in Azure Sentinel involves checking the user's permissions and access history. This is crucial because understanding the user's entitlements and past access patterns provides context about whether the activity observed is consistent or indicative of a potential security incident.

By reviewing the user's permissions, you can determine if any unauthorized access was attempted or if there has been a change in permissions that could facilitate malicious actions. Access history further aids in identifying recent logins, the sources of those logins, and any unusual activities that have taken place, which may highlight the nature and scope of the suspicious activity.

Informed analysis of permissions and historical access is fundamental for prioritizing the investigation and for deciding on subsequent steps to take, whether that's further deep-dive investigations or implementing remediation measures.