Detection rules › Splunk

Disable Defender Enhanced Notification

Status
production
Severity
medium
Group by
TargetObject, computer_name, details, event_type, process_guid, process_id, registry_hive, registry_path, registry_status, registry_value_name, registry_value_type, user, vendor_product
Author
Teoderick Contreras, Splunk, Steven Dick
Source
github.com/splunk/security_content

The following analytic detects the modification of the registry to disable Windows Defender's Enhanced Notification feature. It leverages data from Endpoint Detection and Response (EDR) agents, specifically monitoring changes to the registry path associated with Windows Defender reporting. This activity is significant because disabling Enhanced Notifications can prevent users and administrators from receiving critical security alerts, potentially allowing malicious activities to go unnoticed. If confirmed malicious, this action could enable an attacker to bypass detection mechanisms, maintain persistence, and escalate their activities without triggering alerts.

MITRE ATT&CK coverage

TacticTechniques
Defense ImpairmentT1685 Disable or Modify Tools

Event coverage

ProviderEventTitle
SysmonEvent ID 13RegistryEvent (Value Set)

Rule body splunk

name: Disable Defender Enhanced Notification
id: dc65678c-301f-11ec-8e30-acde48001122
version: 15
creation_date: '2021-10-18'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk, Steven Dick
status: production
type: TTP
description: The following analytic detects the modification of the registry to disable Windows Defender's Enhanced Notification feature. It leverages data from Endpoint Detection and Response (EDR) agents, specifically monitoring changes to the registry path associated with Windows Defender reporting. This activity is significant because disabling Enhanced Notifications can prevent users and administrators from receiving critical security alerts, potentially allowing malicious activities to go unnoticed. If confirmed malicious, this action could enable an attacker to bypass detection mechanisms, maintain persistence, and escalate their activities without triggering alerts.
data_source:
    - Sysmon EventID 13
search: '| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path = "*Microsoft\\Windows Defender\\Reporting*" Registry.registry_value_name = DisableEnhancedNotifications Registry.registry_value_data = 0x00000001) by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `disable_defender_enhanced_notification_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: user may choose to disable windows defender AV
references:
    - https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/
drilldown_searches:
    - name: View the detection results for - "$dest$" and "$user$"
      search: '%original_detection_search% | search  dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") | 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: modified/added/deleted registry entry $registry_path$ on $dest$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: modified/added/deleted registry entry $registry_path$ on $dest$
analytic_story:
    - Azorult
    - CISA AA23-347A
    - IcedID
    - Windows Registry Abuse
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/malware/icedid/disable_av/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path = "*Microsoft\\Windows Defender\\Reporting*" Registry.registry_value_name = DisableEnhancedNotifications Registry.registry_value_data = 0x00000001) by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product

Stage 2: search

| `drop_dm_object_name(Registry)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `disable_defender_enhanced_notification_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Registry.registry_patheq
  • "*Microsoft\\Windows Defender\\Reporting*"
Registry.registry_value_dataeq
  • 0x00000001 corpus 63 (splunk 54, elastic 9)
Registry.registry_value_nameeq
  • DisableEnhancedNotifications corpus 2 (elastic 1, splunk 1)