In Splunk Enterprise versions below 10.4.4 and 10.2.8, a user who does not hold the "admin" or "power" Splunk roles could derive the PostgreSQL sidecar database superuser password and run arbitrary operating system commands as the user account running Splunk Enterprise on search head cluster members.
The vulnerability is possible because the PostgreSQL sidecar service derives a privileged database password from the search head cluster identifier that appears in search job logs.
For more information see About configuring role-based user access (https://help.splunk.com/en/splunk-enterprise/administer/manage-users-and-security/10.2/manage-splunk-platform-users-and-roles/about-configuring-role-based-user-access), server.conf (https://help.splunk.com/en/splunk-enterprise/administer/admin-manual/10.2/configuration-file-reference/10.2.0-configuration-file-reference/server.conf), and Sidecar configuration settings (https://help.splunk.com/en/splunk-enterprise/administer/admin-manual/10.4/splunk-sidecars/sidecar-configuration-settings) in the Splunk documentation.