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Description

The following analytic detects the use of a PowerShell commandlet to import an AppLocker XML policy. This behavior is identified by monitoring processes that execute the "Import-Module Applocker" and "Set-AppLockerPolicy" commands with the "-XMLPolicy" parameter. This activity is significant because it can indicate an attempt to disable or bypass security controls, as seen in the Azorult malware. If confirmed malicious, this could allow an attacker to disable antivirus products, leading to further compromise and persistence within the environment.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-23
  • Author: Teoderick Contreras, Splunk
  • ID: 467ed9d9-8035-470e-ad5e-ae5189283033

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_powershell` AND Processes.process="*Import-Module Applocker*" AND Processes.process="*Set-AppLockerPolicy *"  AND Processes.process="* -XMLPolicy *" by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_impair_defense_add_xml_applocker_rules_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_impair_defense_add_xml_applocker_rules_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
  • Registry.registry_key_name
  • Registry.registry_path
  • Registry.user
  • Registry.dest
  • Registry.registry_value_name
  • Registry.action

How To Implement

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

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

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 Applocker importing xml policy command was executed in $dest$

: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