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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.

  • Type: Hunting

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-27
  • Author: Lou Stella, Splunk
  • ID: 3c162281-7edb-4ebc-b9a4-5087aaf28fa7

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1587.003 Digital Certificates Resource Development
Kill Chain Phase
  • Weaponization
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


1
2
3
4
5
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8
9



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

Macros

The SPL above uses the following Macros:

:information_source: splunk_digital_certificates_infrastructure_version_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • none

How To Implement

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

RBA

Risk Score Impact Confidence Message
50.0 50 100 $splunk_server$ may not be properly validating TLS Certificates

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

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 | version: 2