According to Splunk CIM documentation, which field in the Authentication Data Model represents the user...

In theSplunk Common Information Model (CIM), the Authentication Data Model defines standardized field names to normalize data from various sources. For privilege escalation events, the user who initiates the escalation (i.e., the actor performing the elevated action) is represented by the fieldsrc_user. This field captures the source or originating user account involved in the authentication event.

src_user: Typically refers to the user who initiated the action, such as the account escalating privileges.

dest_user: Refers to the target user account involved, such as the user being impersonated or the elevated account.

src_user_idandusernameare either deprecated or less precise in CIM for privilege escalation contexts.

TheSplunk CIM documentation(specifically the Authentication Data Model section) states thatsrc_useris the correct normalized field to capture the initiating user in escalation or impersonation events, supporting consistent searches, alerts, and dashboards across varied log sources.