LoFP LoFP / 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.

Techniques

Sample rules

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.

Detection logic


| tstats `security_content_summariesonly` 
  count min(_time) as firstTime 
        max(_time) as lastTime 
        
from datamodel=Endpoint.Processes where 

Processes.process IN ("*Add-MpPreference *", "*Set-MpPreference *")

Processes.process IN (
      "*-AttackSurfaceReductionRules_Actions*",
      "*-ThreatIDDefaultAction_Actions*"
      )

Processes.process IN (
      "*Allow*", 
      "*NoAction*", 
      "*Disabled*", 
      "*_Actions 6*", 
      "*_Actions 9*", 
      "*_Actions 0*")

by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
   Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
   Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec
   Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level
   Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product


| `drop_dm_object_name(Processes)` 

| `security_content_ctime(firstTime)` 

| `security_content_ctime(lastTime)`

| `windows_defender_asr_or_threat_configuration_tamper_filter`