The following analytic uses tags of SSL, TLS and certificate to identify the usage of the Splunk default certificates being utilized in the environment. Recommended guidance is to utilize valid TLS certificates which documentation may be found in Splunk Docs - https://docs.splunk.com/Documentation/Splunk/8.2.6/Security/AboutsecuringyourSplunkconfigurationwithSSL.
- Type: Hunting
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2022-05-25
- Author: Michael Haag, Splunk
- ID: 620fbb89-86fd-4e2e-925f-738374277586
Kill Chain Phase
- CIS 13
|The httplib and urllib Python libraries that Splunk shipped with Splunk Enterprise did not validate certificates using the certificate authority (CA) certificate stores by default in Splunk Enterprise versions before 9.0 and Splunk Cloud Platform versions before 8.2.2203. Python 3 client libraries now verify server certificates by default and use the appropriate CA certificate stores for each library. Apps and add-ons that include their own HTTP libraries are not affected. For Splunk Enterprise, update to Splunk Enterprise version 9.0 and Configure TLS host name validation for Splunk-to-Splunk communications (https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation) to enable the remediation.
|Splunk Enterprise peers in Splunk Enterprise versions before 9.0 and Splunk Cloud Platform versions before 8.2.2203 did not validate the TLS certificates during Splunk-to-Splunk communications by default. Splunk peer communications configured properly with valid certificates were not vulnerable. However, an attacker with administrator credentials could add a peer without a valid certificate and connections from misconfigured nodes without valid certificates did not fail by default. For Splunk Enterprise, update to Splunk Enterprise version 9.0 and Configure TLS host name validation for Splunk-to-Splunk communications (https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation) to enable the remediation.
tag IN (ssl, tls, certificate) ssl_issuer_common_name=*splunk*
| stats values(src) AS "Host(s) with Default Cert" count by ssl_issuer ssl_subject_common_name ssl_subject_organization ssl_subject host sourcetype
The SPL above uses the following Macros:
splunk_identified_ssl_tls_certificates_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
Ingestion of SSL/TLS data is needed and to be tagged properly as ssl, tls or certificate. This data may come from a proxy, zeek, or Splunk Streams. Splunk SOAR customers can find a SOAR workbook that walks an analyst through the process of running these hunting searches in the references list of this detection. In order to use this workbook, a user will need to run a curl command to post the file to their SOAR instance such as "curl -u username:password https://soar.instance.name/rest/rest/workbook_template -d @splunk_psa_0622.json". A user should then create an empty container or case, attach the workbook, and begin working through the tasks.
Known False Positives
False positives will not be present as it is meant to assist with identifying default certificates being utilized.
Associated Analytic Story
|The following $host$ is using the self signed Splunk certificate.
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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