Detection: Splunk Digital Certificates Infrastructure Version

Description

The following analytic identifies improper TLS validation configuration on Splunk search heads and peers post version 9. It leverages REST API calls to retrieve server information and SSL configuration settings, checking fields like sslVerifyServerCert and sslVerifyServerName. This activity is significant for a SOC as improper TLS settings can expose the infrastructure to man-in-the-middle attacks and data breaches. If confirmed malicious, attackers could intercept or manipulate data, compromising the integrity and confidentiality of communications within the Splunk environment.

Search

1
2| rest /services/server/info 
3| table splunk_server version server_roles 
4| join splunk_server [
5| rest /servicesNS/nobody/search/configs/conf-server/ search="sslConfig"
6| table splunk_server sslVerifyServerCert sslVerifyServerName serverCert] 
7| fillnull value="Not Set" 
8| rename sslVerifyServerCert as "Server.conf:SslConfig:sslVerifyServerCert", sslVerifyServerName as "Server.conf:SslConfig:sslVerifyServerName", serverCert as "Server.conf:SslConfig:serverCert" 
9| `splunk_digital_certificates_infrastructure_version_filter`

Data Source

Name	Platform	Sourcetype	Source
Splunk	Splunk	'splunkd_ui_access'	'splunkd_ui_access.log'

Macros Used

| splunk_digital_certificates_infrastructure_version_filter | search * |

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

The user running this search is required to have a permission allowing them to dispatch REST requests to indexers (the dispatch_rest_to_indexers capability) in some architectures. 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

No known at this time.

Associated Analytic Story

• Splunk Vulnerabilities

Risk Based Analytics (RBA)

References

• https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation#Configure_TLS_host_name_validation_for_Splunk-to-Splunk_communication

• https://www.splunk.com/en_us/product-security/announcements/svd-2022-0602.html

• https://www.github.com/splunk/security_content/blob/develop/workbooks/splunk_psa_0622.json

Detection Testing

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 3