Denial of Service (DoS) through Splunk Web Content-Type Header Parsing in Splunk Enterprise

Overview

In Splunk Enterprise versions below 10.4.4, 10.2.8, 10.0.11, and 9.4.16, an unauthenticated user could send a single crafted request to the Splunk Web JavaScript logger endpoint and cause Splunk Web to stop responding to requests. Splunk Web remains unavailable until Splunk Enterprise is restarted. The vulnerability is possible because Splunk Web does not limit request-header parsing before processing the request.

Affected

• enterprise >= 10.4 < 10.4.4
• enterprise >= 10.2 < 10.2.8
• enterprise >= 10.0 < 10.0.11
• enterprise >= 9.4 < 9.4.16

Remediation

Upgrade Splunk Enterprise to versions 10.4.4, 10.2.8, 10.0.11, and 9.4.16 or higher.

Workarounds

The vulnerability affects instances with Splunk Web turned on. Turning Splunk Web off is a possible workaround. See Disable unnecessary Splunk Enterprise components and the web.conf configuration specification file for more information on turning off Splunk Web.