Add or Set Windows Defender Exclusion

SPLUNK detection rule by Teoderick Contreras, Nasreddine Bencherchali, Splunk · Apache-2.0

The following analytic detects the use of commands to add or set exclusions in Windows Defender. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving "Add-MpPreference" or "Set-MpPreference" with exclusion parameters. 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.

name: Add or Set Windows Defender Exclusion
id: 773b66fe-4dd9-11ec-8289-acde48001122
version: 18
creation_date: '2021-11-25'
modification_date: '2026-06-08'
author: Teoderick Contreras, Nasreddine Bencherchali, Splunk
status: production
type: TTP
description: |
    The following analytic detects the use of commands to add or set exclusions
    in Windows Defender. It leverages data from Endpoint Detection and Response (EDR)
    agents, focusing on command-line executions involving "Add-MpPreference" or "Set-MpPreference"
    with exclusion parameters. 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.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
    as lastTime from datamodel=Endpoint.Processes where
    (
      Processes.process = "*Add-MpPreference *"
      OR
      Processes.process = "*Set-MpPreference *"
    )
    Processes.process IN (
          "*-Exclusion*",
          "*-ControlledFolderAccessAllowedApplications*",
          "*-AttackSurfaceReductionOnlyExclusions*"
          )
    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)`
    | `add_or_set_windows_defender_exclusion_filter`
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: |
    Admin or user may choose to use this windows features. Filter as needed.
references:
    - https://tccontre.blogspot.com/2020/01/remcos-rat-evading-windows-defender-av.html
    - https://app.any.run/tasks/cf1245de-06a7-4366-8209-8e3006f2bfe5/
    - https://www.microsoft.com/security/blog/2022/01/15/destructive-malware-targeting-ukrainian-organizations/
    - https://learn.microsoft.com/en-us/powershell/module/defender/add-mppreference?view=windowsserver2025-ps
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: exclusion command $process$ executed on $dest$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: exclusion command $process$ executed on $dest$
analytic_story:
    - Compromised Windows Host
    - AgentTesla
    - Data Destruction
    - Remcos
    - CISA AA22-320A
    - ValleyRAT
    - XWorm
    - WhisperGate
    - Windows Defense Evasion Tactics
    - Crypto Stealer
    - NetSupport RMM Tool Abuse
    - Salat Stealer
asset_type: Endpoint
mitre_attack_id:
    - T1685
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.001/defender_exclusion_sysmon/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

2477453d-25ef-43e5-b71f-9fe7ed9fafea

Propose edits, view related rules, and engage with the community through comments.

Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

Community Discussion