In Splunk Enterprise versions below 10.4.2, 10.2.6, 10.0.9, and 9.4.14, and Splunk Secure Gateway versions below 3.10.10, 3.9.24, and 3.8.71, a user who does not hold the "admin" or "power" Splunk roles could register an arbitrary companion app and cause Splunk Secure Gateway to forward mobile user requests, including tokens that compromise all relevant data available to the affected mobile user, to an attacker-controlled Uniform Resource Locator (URL). The vulnerability is possible because a hard-coded cryptographic key in the Splunk Secure Gateway companion app registration handler allows for arbitrary callback URL registration without restriction. For more information see Define roles on the Splunk platform with capabilities (https://help.splunk.com/en/splunk-enterprise/administer/manage-users-and-security/10.2/manage-splunk-platform-users-and-roles/define-roles-on-the-splunk-platform-with-capabilities) in the Splunk documentation.
Upgrade Splunk Secure Gateway to versions 3.10.10, 3.9.24, and 3.8.71, or higher. If you are not able to upgrade Splunk Enterprise or Splunk Secure Gateway, turn off or remove the Splunk Secure Gateway app. See Manage app and add-on objects in the Splunk documentation. Note: Splunk Mobile, Spacebridge, and Mission Control rely on functionality in the Splunk Secure Gateway app. If you do not use any of these apps, features, or functionality, as a potential mitigation, you may turn off or remove the app.
Upgrade Splunk Enterprise to versions 10.4.2, 10.2.6, 10.0.9, and 9.4.14, or higher.