Path Traversal through the Lookup Configuration REST API in Splunk Enterprise

In Splunk Enterprise versions below 10.4.2, 10.2.6, 10.0.9, and 9.4.14, a user who does not hold the "admin" or "power" Splunk roles could move files that the user account running Splunk Enterprise can read into a lookup that the user controls. The user could then access all relevant data and affect system integrity and availability on the search head. The vulnerability is possible because the lookup configuration endpoint does not resolve lookup source paths before checking whether they stay inside the allowed lookup staging area. For more information see About lookups (https://help.splunk.com/en/splunk-enterprise/manage-knowledge-objects/knowledge-management-manual/10.4/use-lookups-in-splunk-web/about-lookups) and Define roles on the Splunk platform with capabilities (https://help.splunk.com/en/splunk-enterprise/administer/manage-users-and-security/10.4/manage-splunk-platform-users-and-roles/define-roles-on-the-splunk-platform-with-capabilities) in the Splunk documentation.