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Description

On June 14th 2022, Splunk released vulnerability advisory addresing Python TLS validation which was not set before Splunk version 9. This search displays events showing WARNING of using Splunk issued default selfsigned certificates.

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

  • Last Updated: 2022-05-26
  • Author: Rod Soto, Splunk
  • ID: c76c7a2e-df49-414a-bb36-dce2683770de

Annotations

ATT&CK
ID Technique Tactic
T1588.004 Digital Certificates Resource Development
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
ID Summary CVSS
CVE-2022-32152 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. 6.5
1
2
3
`splunkd` certificate event_message="X509 certificate* should not be used*" 
| stats count by host CN component log_level 
| `splunk_protocol_impersonation_weak_encryption_selfsigned_filter`

Macros

The SPL above uses the following Macros:

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

Required field

  • host
  • CN
  • event_message

How To Implement

Must upgrade to Splunk version 9 and Configure TLS in order to apply this search. 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

This searches finds self signed certificates issued by Splunk which are not recommended from Splunk version 9 forward.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
40.0 50 80 Splunk default issued certificate at $host$

: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: 1