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Description

The following analytic is to identify the imports of Windows PowerShell Applocker commandlets. This technique was seen in Azorult malware where it drops an xml Applocker policy that will deny several AV product and then loaded using PowerShell Applocker commandlet.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-06-30
  • Author: Teoderick Contreras, Splunk
  • ID: 102af98d-0ca3-4aa4-98d6-7ab2b98b955a

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1059.001 PowerShell Execution
T1059 Command and Scripting Interpreter Execution
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE 


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`powershell` EventCode=4104 ScriptBlockText="*Import-Module Applocker*" ScriptBlockText="*Set-AppLockerPolicy *" ScriptBlockText="* -XMLPolicy *" 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer user_id 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_powershell_import_applocker_policy_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_powershell_import_applocker_policy_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
  • Computer
  • 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

administrators may execute this command that may cause some false positive.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 A PowerShell script contains Import Applocker Policy command $ScriptBlockText$ with EventCode $EventCode$ in host $Computer$

: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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