Splunk Enterprise must be configured to protect the log data stored in the indexes from alteration.

Without non-repudiation, it is impossible to positively attribute an action to an individual (or process acting on behalf of an individual). The records stored by Splunk Enterprise must be protected against alteration. A hash is one way of performing this function. The server must not allow the removal of identifiers or date/time, or it must severely restrict the ability to do so.