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.
Query · spl
| 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`
Implementation guide
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.
Analyst notes
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.