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Description

The following analytic identifies the PowerShell Cmdlet export-pfxcertificate utilizing Script Block Logging. This particular behavior is related to an adversary attempting to steal certificates local to the Windows endpoint within the Certificate Store.

  • Type: Anomaly

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

  • Last Updated: 2023-02-01
  • Author: Michael Haag, Splunk
  • ID: ed06725f-6da6-439f-9dcc-ab30e891297c

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1552.004 Private Keys Credential Access
T1552 Unsecured Credentials Credential Access
T1649 Steal or Forge Authentication Certificates Credential Access
Kill Chain Phase
  • Actions on Objectives
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE 


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`powershell` EventCode=4104 ScriptBlockText IN ("*export-pfxcertificate*") 
| rename Computer as dest  
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText dest user_id 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_powershell_export_pfxcertificate_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_powershell_export_pfxcertificate_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.

  • _time
  • ScriptBlockText
  • dest
  • EventCode

How To Implement

To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.

Known False Positives

It is possible administrators or scripts may run these commands, filtering may be required.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
36.0 60 60 A PowerShell Cmdlet related to exporting a PFX Certificate was ran on $dest$, attempting to export a certificate.

: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

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