Detection: Windows Defender ASR or Threat Configuration Tamper

Description

The following analytic detects the use of commands to disable Attack Surface Reduction (ASR) rules or change threat default actions in Windows Defender. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving "Add-MpPreference" or "Set-MpPreference". This activity is significant because adversaries often use it to bypass Windows Defender, allowing malicious code to execute undetected. If confirmed malicious, this behavior could enable attackers to evade antivirus detection, maintain persistence, and execute further malicious activities without interference from Windows Defender.

Search

 1
 2| tstats `security_content_summariesonly` 
 3  count min(_time) as firstTime 
 4        max(_time) as lastTime 
 5        
 6from datamodel=Endpoint.Processes where 
 7
 8Processes.process IN ("*Add-MpPreference *", "*Set-MpPreference *")
 9
10Processes.process IN (
11      "*-AttackSurfaceReductionRules_Actions*",
12      "*-ThreatIDDefaultAction_Actions*"
13      )
14
15Processes.process IN (
16      "*Allow*", 
17      "*NoAction*", 
18      "*Disabled*", 
19      "*_Actions 6*", 
20      "*_Actions 9*", 
21      "*_Actions 0*")
22
23by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
24   Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
25   Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec
26   Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level
27   Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
28
29
30| `drop_dm_object_name(Processes)` 
31
32| `security_content_ctime(firstTime)` 
33
34| `security_content_ctime(lastTime)`
35
36| `windows_defender_asr_or_threat_configuration_tamper_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	N/A	'crowdstrike:events:sensor'	'crowdstrike'
Sysmon EventID 1	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688	Windows	'XmlWinEventLog'	'XmlWinEventLog:Security'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

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

Certain administrative tasks may require the modification of ASR rules or threat actions due to FPs being generated. Investigate all attempts and filter as needed.

Associated Analytic Story

• Windows Defense Evasion Tactics

Risk Based Analytics (RBA)

Risk Message:

ASR or Threat detection tamper activity executed via $process$ on $dest$

References

• https://learn.microsoft.com/en-us/powershell/module/defender/set-mppreference?view=windowsserver2025-ps#-attacksurfacereductionrules-actions

• https://www.virustotal.com/gui/file/7e805617c313ec2fb59d86719c827074cb7dfbf8f0aa18194ac1ffe6c21c8967/behavior

Detection Testing

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: GitHub | Version: 1