Splunk Enterprise and Universal Forwarder CLI connections lacked TLS certificate validation

Description

In Splunk Enterprise and Universal Forwarder versions before 9.0, the Splunk command-line interface (CLI) did not validate TLS certificates while connecting to a remote Splunk platform instance by default. Splunk peer communications configured properly with valid certificates were not vulnerable. However, connections from misconfigured nodes without valid certificates did not fail by default. After updating to version 9.0, see Configure TLS host name validation for the Splunk CLI to enable the remediation.

The vulnerability does not affect the Splunk Cloud Platform. At the time of publishing, we have no evidence of exploitation of this vulnerability by external parties.

Solution

Upgrade Splunk Enterprise and Universal Forwarder versions to 9.0 or higher and Configure TLS host name validation for the Splunk CLI.

Product Status

Severity Considerations

Splunk strongly recommends securing your Splunk environment with hardened TLS configurations. See Securing the Splunk platform with TLS for more information. However, the vulnerability assumes that you have configured your Splunk platform instances to use transport layer security (TLS) certificates for secure network connections. If you have not and are using the default certificates, the vulnerability is not applicable and is informational.

Acknowledgments

Chris Green at Splunk

Changelog

2022-07-18: Added Severity Considerations