What is an essential function of the Splunk ES incident review?

The essential function of the Splunk ES incident review is to document investigative processes and resolutions. This is crucial in the context of incident management, as it allows security analysts to track the investigation steps taken for each incident and the outcomes of those investigations. Having a documented process serves multiple purposes: it ensures accountability, helps in the analysis of previous incidents to identify trends or recurring issues, provides a reference for future incidents, and may also support compliance requirements where documentation of incidents is necessary.

In contrast, the other options do not align with the primary focus of the incident review function. Reconfiguring user roles is more related to user management and access control. Analyzing historical search patterns may be part of general Splunk usage but does not specifically pertain to the process of incident reviews. Establishing firewall rules is a security configuration task that does not connect directly to the incident investigation and resolution documentation responsibilities of the incident review function.